Site deaths are when sites go offline, taking their content and permalinks with them, and breaking the web accordingly. Site deaths are one of the big reasons why you should own your own identity and content on the web.
This is a chronology of content hosting sites that have died, removing millions (billions?) of permalinks from the web. This is specifically for content hosting sites which permitted end-user posting. Not random sites nor pure "app" sites where there's no loss of user data. If a game site goes down and takes down play history/scores, or if Gmail went away those would both represent loss of user data (though no public permalinks).
The tendency for big companies to shut down a service and delete all your things has now even been satirised by XKCD. Andy Baio talks through one example from creation, to growth, acquisition, disillusionment, neglect, and shutdown.
This is a partial list, please add more, e.g. from other sources like:
Expected/announced site deaths. Check them upon announced shutdown date.
- If site shutdown is confirmed, move to #Past by year.
- If site is still up as of shutdown date, move to #Any_Day_Now
- 2015-??-?? Rdio shutting down imminently.
- Bankrupt and assets being acquired by Pandora.
- Rdio blog on 2015-11-16 :
Rdio's service will not be interrupted today. We will have more updates in the coming weeks on what this process means for your Rdio account, but for the time being the service continues unchanged.
- 2016-01-25 Google Code 
- "March 12, 2015 - New project creation disabled."
- "August 24, 2015 - The site goes read-only. You can still checkout/view project source, issues, and wikis."
- "January 25, 2016 - The project hosting service is closed. You will be able to download a tarball of project source, issues, and wikis. These tarballs will be available throughout the rest of 2016."
- From the comments: "I work on Google Code, and we will be putting a service in place to redirect deep links to project homepages, issues, etc. to their new locations."
- 2016-08-31 Google Drive 
- Beginning August 31st, 2015, web hosting in Google Drive for users and developers will be deprecated. You can continue to use this feature for a period of one year until August 31st, 2016, when we will discontinue serving content via googledrive.com/host/[doc id].
- 2016-09 Orkut Export shuts down.
- 2014-09-30 Orkut shut down. Public archives read-only archives available at https://orkut.google.com/
- "We are preserving an archive of all public communities, which will be available online starting September 30, 2014. If you don't want your posts or name to be included in the community archive, you can remove Orkut permanently from your Google account." 
- "People can export their profile data, community posts and photos using Google Takeout (available until September 2016)" (ibid)
Any Day Now
These sites are officially closed, but some functionality may still be working (e.g. logging in and viewing your activity).
- 2015-07-24 frontback 
- "Frontback as a service will be winding down on August 15th. On this page we provide you with an easy way to export all your photos. Your data will be available to download until September 15th, 2015. After this date, all photos and data will be permanently deleted from our servers."
- 2014-05-16 Loom cloud-based photo storage
- Announced being acquired by DropBox 2014-04-17.  
- No longer enrolling new users. Existing Loom users can continue to use our service until May 16, 2014
- 2014-05-31, 2015-01-19 site appears to still be up for existing users. - Tantek
- 2014-09-25 TwitPic announced it would be shut down, but on 2014-09-18 TwitPic stated it was acquired and would not be shut down.
- "We're happy to announce we've been acquired and Twitpic will live on! We will post more details as we can disclose them"
- Original reason for the shutdown announcement:
A few weeks ago Twitter contacted our legal demanding that we abandon our trademark application or risk losing access to their API. [..] Unfortunately we do not have the resources to fend off a large company like Twitter to maintain our mark which we believe whole heartedly is rightfully ours. Therefore, we have decided to shut down Twitpic.
- Data export:
You will be able to export all your photos and videos. We’ll let everyone know when this feature is live in the next few days.
- 2014-10-25 Twitpic’s Future
[…] we have reached an agreement with Twitter to give them the Twitpic domain and photo archive, thus keeping the photos and links alive for the time being. Emphasis added, thus implying domain and permalinks still at risk.
- 2014-12-31 Yahoo! Directory  
- 2015-01-19 dir.yahoo.com and directory.yahoo.com redirect to business.yahoo.com, still appear to be visible but perhaps not changing.
This is an incomplete list. Please help by adding examples from these sources (in particular when user authored content was lost):
See also (and add one-line summaries to) the history page.
In reverse chronological order:
Comcast/Xfinity Personal Web Pages
- 2015-10-08 Comcast/Xfinity Personal Web Pages 
- announced around 2015-07-06
- As of 2015-11-20, Comcast Personal Web Pages return a 404 with the message "Error: Your request of "[username].home.comcast.net" was not found on redirect platform."
- 2015-08-30 read-only; 2015-09-30 closed. Yahoo Pipes 
Pipes creation will not be supported as of Aug. 30 this year. Pipes infrastructure will run until Sept. 30, 2015 in read-only mode to help developers migrate their data. Please visit http://pipes.yahoo.com/pipes for additional details.
- 2015-09-29 plug.dj 
- Closed the same day as announcement.
Unfortunately, we didn’t get enough support through our subscribers to keep the site running month to month. We’re truly thankful for the donations we received that helped keep the site up until now. If it wasn’t for you, the site would have shut down 3 weeks ago. For the people who are currently subscribed, all active subscriptions will be cancelled today. At 3PM PDT we’ll be shutting our doors.
This Is My Jam
- 2015-09-26 This Is My Jam 
This Is My Jam will become a read-only time capsule on September 26, 2015. This means you won’t be able to post anymore, but you’ll be able to browse a new archive version of the site.
Your profile data (jams, loves, etc) will also be exportable in a few formats, including text lists; the read-only API will stay online for developers who want to play; we’ll also be open sourcing as much code as we can on Github.
- 2015-08-01 - Google+ Photos begins to shut down. Google+ Photos was a photo service integrated into Google+. In May of 2015, Google created a new photos product that had no relationship with Google+. Since all information was migrated, and it is still a service of the same company, incorporating many of the same features, it could be considered more of a 'spinoff'.
- 2015-06-30 Yahoo Maps 
The Yahoo Maps site will close at the end of June. However, in the context of Yahoo search and on several other Yahoo properties including Flickr, we will continue to support maps. We made this decision to better align resources to Yahoo’s priorities as our business has evolved since we first launched Yahoo Maps eight years ago.
- 2015-07-22 http://maps.yahoo.com now redirects to a Yahoo search for "maps"
- 2015-06-11 Balanced Payments 
We started building a payments service for marketplaces in 2011. We were shocked with the state of payments at the time, and the pains a marketplace had to go through. Unfortunately, we haven't been able to reach the escape velocity necessary to be a large, innovative, independent player in the payments space and have decided not to continue building Balanced. We reached out to Stripe and have been working with them to provide a smooth path forward for our customers. Our full API and dashboard will be available until June 11, 2015, and support for issuing refunds, querying transactions, and fighting chargebacks will continue until October 9, 2015.
- 2015-06-03 Branch discussion service shutdown, as well as related site Potluck
- ???? user profiles lost
- ???? discussion posts lost, including this about silos vs. the indieweb:
- 2014-01-13 Facebook acquired Branch and Potluck
- 2015-04-30 Lyrk.de map tile service (copy of email sent to tommorris)
- "We are really proud to have created an OpenStreetMap map style that has raised the bar in terms of accuracy and visual quality, but weren't able to create a sustainable business."
Grooveshark (grooveshark.com) was a streaming music service.
- 2015-04-30 Grooveshark shutdown 
- 1000s user profiles lost
- ???? listening history lost
According to Google's Timetable. Unsure if actual shut down dates differed. This was only noticed after a tweet lamenting the takedown
- 2015-04-20 OpenID 2.0 is shut down. A static error page will be displayed on all requests.
- 2015-03-23 Grace period for developers using the openid_shutdown_ack parameter ends, warning is shown and auto-approval turned off for all applications.
- 2015-02-23 Auto-approval is turned off, users must consent on each request. Developers passing openid_shutdown_ack are unaffected.
- 2015-01-12 Auto-approval is progressivly disabled for more and more users, these users will be forced to re-consent. Developers passing openid_shutdown_ack are unaffected.
- 2014-12-01 Auto-approval is disabled for a small number of requests on an intermittent basis, some users will be forced to re-consent.
- 2014-11-18 User-facing warning message may be shown on consent dialogs, directing users to this help article. Developers may suppress deprecation warnings by adding the openid_shutdown_ack parameter, as specified above.
- 2015-03-31 Trovebox 
- Users have until March 15, 2015 to grab an archive of their photos before the service shuts.
- The service was open source though, so you can keep running your instance yourself. It will also be continued by at least one IndieHoster.
- 2015-04-10 FriendFeed shutdown(per Wikipedia article).
- 2015-04-09 shutdown expected
- ". . . the number of people using FriendFeed has been steadily declining and the community is now just a fraction of what it once was. Given this, we've decided that it's time to start winding things down. Beginning today, we will no longer accept new signups. You will be able to view your posts, messages, and photos until April 9th. On April 9th, we'll be shutting down FriendFeed and it will no longer be available."
- Via http://recode.net/2015/03/09/facebook-shuts-down-friendfeed/
- ???? FriendFeed user profiles lost
- ???? FriendFeed posts lost, permalinks broken
- 2015-01-01 tvtag (tvtag.com) shut down. "Effective January 1st, tvtag is offline. Thanks for tagging along!" It was for checking into TV shows.
- "If you're interested in requesting a copy of your data, please email your username in the subject line to email@example.com"
- ???? tvtag user profiles lost
- ???? tvtag checkins lost
- 2014-11-14 Netflix shut down their API.
- Announced in a blog post 2014-06-13 :
To better focus our efforts and to align them with the needs of our global member base, we will be retiring the public API program. Effective on November 14, 2014, public API developers will no longer be able to access Netflix content. All requests to the public API will return 404 errors.
- 2014-10-28 43things, a website used to collect and and set personal goals, is shutting down:
- 2014-10-11 Ohlife.com, a small free service allowing people to write a letter to their future self . Users were told that they could save their entries to a text file and given a link to download those files before the shutdown date.
- 2014-09-30 MyFamily.com shutdown by owner Ancestry.com (Slate.com: Deleting the Family Tree: MyFamily shuttered: Ancestry.com deleted 10 years of family history)
- 2014-06-04 MyFamily shutdown announced(see comments on that blog post for user outrage)
- 2014-06-05 MyFamily shutdown announced to happen 2014-09-05
- Export was photos only, all text / correspondence lost
- Over 1.5 million (as of 2004!) user profiles lost 
- Exaggerated claim:
“[u]nlimited storage space and SiteSafeSM technology keep all of your family memories safe and secure. No matter what.”
- 2014-08-?? markbox.io, a small paid hosting service shut down when its single server "simply went away". The guts of the service were simplified and open-sourced as boxpub.
- 2014-08-31: Svpply will be sunset by eBay.
- "We regret to announce that Svpply.com and its associated apps — Svpply and Want by Svpply — will retire on August 31st."
- Export of link data added to the site is available from users' account settings.
- In response, the founder launched a Kickstarter campaign to build a new version of the site, called Very Goods. It was successfully funded on 2014-07-21.
- 2015-01-19 svpply.com simply redirects to www.ebay.com, and pages inside redirect as well, e.g. their sunset announcement svpply.com/sunset redirects to pages.ebay.com/sunset (a 404).
- 2014-08-10 Fotopedia photo encyclopedia and photo album host to be shut down
- Announced 2014-07-31: ". . . your data will be available to download until August 10, 2014. After this date, all photos and data will be permanently deleted from our servers."
- 2014-07-01 Readmill "app will no longer be available ... All of your books, reading data and account information will be permanently deleted. User information will not be archived, shared or saved in any way.".
Export data includes books, followers, followings, readings, highlights, reviews, comments and likes on your highlights and reviews, and highlights you liked.
- ???? Readmill profiles being lost, including followers/followings lists, readings, highlights, reviews, comments, likes, comments and likes on your highlights and reviews, and highlights liked
- ???? purchased ebooks lost
- 2014-07-31 Repost.us "On July 31 2014 we will shutdown the Repost api servers and all embedded content will cease to be available"
- Will redirect API requests to a service that returns errors (to help callers avoid hanging) through 2014-12-31
- Link shortener s.tt remains active through the end of the year 2014-12-31
- 2014-06-25 Springpad "will be shutting down."
2014-06-19 myOpenID.com finally disappeared according to Archive.org.
- 2014-06-17 Codespaces.com experienced a DDOS and an unauthorized person gained access to their EC2 control panel. From http://www.codespaces.com:
. . . removed all EBS snapshots, S3 buckets, all AMI's, some EBS instances and several machine instances.
In summary, most of our data, backups, machine configurations and offsite backups were either partially or completely deleted.
Code Spaces will not be able to operate beyond this point, the cost of resolving this issue to date and the expected cost of refunding customers who have been left without the service they paid for will put Code Spaces in a irreversible position both financially and in terms of on going credibility.
As such at this point in time we have no alternative but to cease trading and concentrate on supporting our affected customers in exporting any remaining data they have left with us.
- 2014-06-15 Justin.tv no longer archiving live broadcasts and will be deleting all archived videos with two weeks notice.
- "All VODs will be removed after June 15, 2014. We recommend downloading your recorded videos before the date."
- Initially this reported "June 8, 2014", but as of 2014-06-24 the page says June 15.
- 2014-05-29 https://help.justin.tv/entries/41803380-Changes-to-Video-Archive-System
- Justin.tv shut down and transferred all focus to gaming-related content platform Twitch Interactive. Videos on Justin.tv are no longer accessible for download. Video archiving and VODs was removed on June 15, 2014.
- Accounts only saved for users who used their justin.tv account to login to Twitch, or signed up for Twitch. Users still using their Justin.tv logins to log into Twitch will need to complete a form to have account transferred to Twitch for full site use.Justin.tv will move your account within 72 hours. Request to transfer account must be received on or before Friday, September 5, 2014. The Justin.tv site reminds users "Twitch is a site for gaming-related content only" and that all content posted to Twitch must follow Twitch TOS.
- Justin.tv accounts tranferred to Twitch will keep the username and email address associated with the Justin.tv Accounts will continue to follow any currently followed Twitch channel, but not any JTV channel, unless that channel is also transferred to Twitch. Users will NOT keep JTV followers, unless those followers have also transferred to Twitch. VODs will not be transferred to Twitch.
- Active Justin.tv Pro Account Users will be refunded. An email to members communicated the cancellation and refund process.
- Mobile apps, APIs, broadcast tool, and all other components of the site no longer work. Users were referred to YouTube, Ustream and Livestream for live video content.
- ???? Lost videos
- ???? Lost user accounts
- Archive.org downloaded all Justin.tv videos with more than 10 views. https://archive.org/details/justintv Archive.org also took requests to download and archive specific videos by request.
- 2014-06-01 Ubuntu One cloud sync service run by Canonical, makers of Ubuntu, to be discontinued.
- ". . . user content will remain available for download until 31 July, at which time it will be deleted."
- 2014-06-?? Spreadly social sharing platform
- Service was shut down because company closed. All data was deleted without providing any kind of export.
- 2014-05-30 Editorially collaborative writing and editing platform
- Service will be shut down; did not get enough users to make it sustainable. Users have until shut down date to export their data. Archive will include a plain text file for every version of every document you have access to; it will also include comments, version notes, tags, activity, and other metadata about your documents. That metadata will be provided in the form of a YAML file. https://editorially.com/help
- 2014-06-24: Announced that Editorially has been acquired by Vox Media and they want to "release parts of the code via an open source license." Interestingly, "Absolutely no user data — no names, email addresses, documents, or any other user data — will be transferred to Vox Media."
- 2014-12-31: "Remaining data backups will be permanently deleted" (until then "users may request a backup of their data by emailing firstname.lastname@example.org" - http://editorially.com/ )
- 2014-03-15 Zootool.com "shutting down". Site already has goodbye message as of 2014-02-10. Email also sent to users with same message dated 2014-02-10.
- Deletion coming:
On March, 15th all data and images will be deleted forever.
- 150,000+ user profiles will be lost
- "millions of collected items" will be lost
- Amazing insight quote in shutdown notice:
Zootool made us realize that the general idea of running a central service is nothing we believe in any longer. Your data should belong to you and shouldn't be stored on our servers. You shouldn't have to rely on us or on any other service to keep your data secure and online.
- Data export promise:
You will have the chance to export your data over the next weeks. We offer export for bookmark files, which can be used to import your bookmarks in all common browsers and most other bookmark services. You can find the export in your Settings.
- 2014-02-14 Read only mode expected:
Starting by the end of this week we are going to switch Zootool into read-only mode. You will still be able to browse your collection, but you will not be able to add new bookmarks.
- 2014-02-27 Donna by Incredible Labs (intelligent personal assistant app)
- Incredible Labs Acquired By Yahoo, Mobile Assistant App Donna To Be Shut Down.
- 2014-01-02 Ptch shut down. Ptch Joins Yahoo. Instructions provided for how to save user content.
2013-12-12 ClaimID "ceased operations" after "7 years, 6 months, and 20 days of service".
- 100,000s profiles / identities lost
2013-12-01 HipGeo travel journal app that allowed people to track their travels and location. Site replaced with a WordPress installation with one post and a default comment. All permalinks from Google search results for the brand broken . ??? profiles lost. Shutdown announcement: 
2013-11-05 Everpix photo content hosting silo announces shutdown, immediately goes "read-only", and says they will "email instructions to all Everpix users on how to download their photos". 
2013-11-05- Sold, a service to help people sell things, was acquired by Dropbox and shut down. *http://usesold.com/
2013-11-01 iGoogle shut down What's happening to iGoogle? The mobile version was retired on 2012-07-31.
2013-11-01 Dopplr discontinued (home page and ).
2013-10-11 DarQroom started as a free photograph storage / publication / printing platform until the end announced by Thierry Ferey - former co-founder and CEO of DarQroom
2013-09-28 Yahoo! Term Extraction API (citation needed)
- We are eliminating direct access to the Yahoo! Term Extraction API and as of September 28, will require developers to go through YQL. We encourage all existing users of the Term Extraction Legacy API to migrate to YQL requests by September 28. You can use the YQL forums for any questions you might have about migrating to YQL. If you are already using the Term Extraction API via YQL, you don’t need to take any action.
2013-09-19- .Net Magazine, a web industry magazine, merged with creative bloq
- how many URLs lost? apparently top 500 articles out of > 9000 were moved with proper redirects, working on moving others
2013-09-01 GeoURL 503 Service Unavailable
- GeoURL is (was) a location-to-URL reverse directory. This will allow you to find URLs by their proximity to a given location
- http://www.crunchbase.com/organization/geourl reports "Organization closed on September 1, 2013"
- At least these two domains: geourl.org & geourl.com
2013-08-05 Yahoo! Astrid (task tracking service)
Yahoo Local API
2013-09-28 Yahoo! Local API
2013-08-21- Alice.com a grocery delivery service, shuts down. Launch article from 2009. http://news.cnet.com/8301-17939_109-10270643-2.html Announcement of Shutdown on YCombinator. https://news.ycombinator.com/item?id=6250893
- how many user accounts were lost?
- as any user content lost?
- were any public permalinks to user content lost?
2013-08-09 Google Latitude retired.
2013-08-09 Silent Circle Maryland-based encrypted private email provider preemptively shut down following suit of Lavabit. Two Providers of Secure E-Mail Shut Down, Silent Circle Preemptively Shuts Down Encrypted Email Service To Prevent NSA Spying
2013-08-08 Lavabit Texas-based encrypted private email provider shut down due to its affiliation with being whistleblower Edward Snowden's email provider since 2010. Lavabit's founder Ladar Levison decided to shut down the service after a cost benefit analysis on whether to shut down the service or become "complicit in crimes against the American people". Lavabit, email service Snowden reportedly used, abruptly shuts down
2013-07-24 Snapjoy shut down after being acquired by Dropbox. article
Yahoo Neighbors Beta
2013-07-08 Yahoo! Neighbors Beta (was local.yahoo.com/neighbors) shutdown.
- Unknown number of user questions & answers lost.
2013-07-01 Google Reader shut down.
- ???? number of (users) / user feed reading lists lost
- ???? number of saved/faved reading items lost
MySpace User Blogs
2013-06-12 Myspace.com User blogs after MySpace redesign. MySpace Punishes Its Few Remaining Friends By Vanishing Their Blogs
2013-04-30 Upcoming.org after being acquired by Yahoo
2013-04-30 Posterous.com Thanks from Posterous after being acquired by Twitter
2013-02-07 EveryBlock.com ultralocal news/information site shutdown with "zero warning". Farewell, neighbors
- ???? friends lists lost. 
- ???? discussion threads lost. (ibid)
Yahoo Voice Phone In Out
2013-01-30 Yahoo! Voice Phone In and Phone Out feature shut down
2013-01-22 Mixel  - social network shut down. (Mixel has been acquired by Etsy)
- App removed from Apple's App store, network shutting down early September (2012-09).
- current Mixels can be shared, bulk export functionality on its way
- ???? user profiles lost
- 2012-12-24 Yahoo! Messenger Public Chat Rooms, Yahoo! Messenger Pingbox, Yahoo! Messenger interoperability with Microsoft Windows Live Messenger, shut down
- 2012-12-03 Twistory 
- Not accepting new users as of 2012-11-07
- Paying users were no longer be billed, and had "several months" to download a .csv of their data
- 2012-10-31 Batch.com photo sharing site shut down. article
- 2012-10-12 DailyBooth photo sharing site shut down. article
- 2012-09-02 picplz - last day to login and download photo archives.
- 2012-07-03 site already shut down
- 2013-08-02 domain not found
- 2012-07-20 KLIK - last day to login and download photo archives
- Going down with the Face.com API due to acquisition by Facebook.
- 2013-08-01 domain not found
- 2012-07-05? Plazes downloads.
- Export was available (for who knows how long) - "you can download and keep your Plazes history" (checked as of 2012-07-05)
- 2012-06-30 site officially shut down. See below.
- 2012-07-03 picplz has shut down.
- 2012-09-03 "Photo archives will be available until September 3, 2102" (ibid)
- picplz shut down planned 
- 2012-06-30 Plazes. 
- Export available (for who knows how long)
- 2012-06-30 Apple MobileMe Gallery, iDisk, iWeb downloads.
- 2012-06-30 Apple MobileMe Gallery, iDisk, iWeb,,email
- as of 2012-07-05 on http://www.me.com: "For a limited time, you can still move your account to iCloud, download your photos from Gallery, and download your files from iDisk."
- who knows how long you can still get your data.
- "Closed." screenshot(on Flickr).
- 2011-06-06 Apple Support Communities: What happens to iWeb when there's no Mobile Me?
- Note first comment: "FYI, Apple is deleting some topics pertaining to people voicing their opinions on iWeb and iDisk. Just be careful."
- 2012-05-30 Tabblo shutdown by HP. Was at http://tabblo.com
- ??? number of photos lost (Archive Team has "almost everything" and is posting them to Archive.org)
- ??? number of "tabblos" (collection of photos) lost
- ??? number of links to photos / tabblos broke
- 2012-01-31 All original Tabblo employees gone (from HP) as well as those they directly hired.
- 2007-03-23 HP acquired Tabblo.
- "five million pictures" (at time of acquisition)
- 2006-06 Tabblo launched. (ibid)
- 2012-05-01 Google Knol discontinued - was at knol.google.com
- 2012-10-01 Download your Knol - til 2012-10-01.
- ??? number of Google Knol pages lost
- ??? number of links to Google Knol pages broke
- 2008-07-23 Google Knol launched to the public.
- 2007-12 Google Knol private beta launch.(ibid)
- 2012-04-30 Google Wave shut down.,
- 2012-01-31 Google Wave went read-only.(ibid)
- ??? number of Google Waves lost
- ??? number of migrated Etherpads lost
- ??? number of links to Google Waves broke
- 2010-08-04 Shutdown implied: "We don’t plan to continue developing Wave as a standalone product, but we will maintain the site at least through the end of the year..."
- 2012-03-11 Gowalla shut down
- ??? number of user profiles lost
- ??? number of user check-in permalinks lost
- 2012-03-01 Google Friend Connect retired for all non-Blogger sites - was at www.google.com/friendconnect
- Export your community data - unknown how long it will be supported.
- limitation: "Export Community is limited to your site’s first 2000 members" (ibid)
- encouraged to transition to Google+: "create a Google+ page and place a Google+ badge on your site".
- 2008-05-12 Google Friend Connect launched.
- 2011-12-15 Google Buzz put into read only mode (Buzz API shut down), subsequently killed in 2014
- ??? number of Google Buzz posts lost
- ??? number of Google Buzz user profiles lost
- ??? links to Google Base posts broke
- 2014-08-16 (or earlier) Google Buzz permalinks stopped working, starting 404ing.
- 2011-12-15 Google Buzz permalinks switched to read-only mode.
- 2011-10-14 Google announced the shut down with only 2 months notice.
- From Gizmodo: Gizmodo RIP Google Buzz
I'd say I'm going to miss Buzz, but to be honest I had all but forgotten about it. Oh well. If you need me, I'll be hanging out on Google Wave.emphasis added.
- 2011-07-11 tr.im URL shortener failed.
- ??? number of tr.im short links lost
- ??? number of links to tr.im URLs broken (across the web, Twitter, etc.)
- 2009-12-31 redirecting promised thru this date (and worked)
- 2009-08-10 went read only. short link creation disabled.
- 2010-12-10 Brightkite shut down - was at brightkite.com
- ??? number of user profiles lost
- ??? number of user check-in permalinks lost
- 2010-09-30 Vox shut down - was at vox.com.
- 2010-09-15 Vox went read-only (ibid)
- ??? number of Vox blogs / posts lost.
- ??? number of migrated Pownce profiles lost.
- ??? links to Vox posts broke.
- 2010-06 icanhaz.com shut down URI shortener
- Had previously stopped accepting new URIs but continued to serve old ones
- 55437 short URIs lost
- 2010-05-15 Etherpad.com offline taken offline by Google. (including their own blog post of their transition: http://etherpad.com/ep/blog/posts/transition-update). Etherpad went read-only a month beforehand (2010-04-14).
- ??? number of Etherpad pages lost.
- ??? links to Etherpad pages broke.
- Migration advised: to Google Wave. "Current EtherPad users will also be getting invites to try Google Wave in the near future...", "EtherPad users got invites to use Wave..."
- 2010-05-14 Twine taken offline at twine.com by Evri and redirected to evri.com.
- 2010-03-11 Evry acquired Twine.
- ??? number of Twine pages lost.
- ??? links to Twine pages broke.
- 2008-10-21 Twine launched publicly
- 2009-12-31 Radio Userland service closing. 
- ?? number of blog posts lost
- ?? hosted comments and trackbacks lost
- 2009-12-29 Haloscan commenting service shut down.
- ??? number of comments lost
- ??? number of links to comments broken
- ??? number of blogs with embedded Haloscan commenting broken
- 2009-08-24 Microsoft Popfly went offline
- Warning given on 2009-07-16
- ??? number of user-created sites gone
- 2009-04 Dodgeball.com shut down by Google
- ??? number of Dodgeball profiles gone.
- ??? number of Dodgeball venues gone (user created)
- ??? number of venue reviews gone (user created)
- 2009-02-28(?) went read-only at "end of February"
- 2009-01-14 Shut down announced by Google
- Subsequent site: Google Latitude.
- 2009-02 Pownce.com went offline. Was previously scheduled to go offline 2008-12-15, but voluntary code patches/contributions from Tantek helped them to transition to public read-only access (to increase chance of archival of content) on that date for about 2 months.
- 2008-12-15 went read-only.
- ??? number of Pownce profiles gone.
- ??? links to Pownce posts broken.
- Migration Advised: import to Vox: "Six Apart is encouraging Pownce members to join its blog platform Vox".
- 2009-01-30 Ma.gnolia.com shutdown.. Ma.gnolia.com suffered catastrophic database corruption and lost all user data.
- 2008-03 Consumating.com shut down by CNET.
- ??? number of Consumating profiles/posts lost.
- ??? links to Consumating posts broken.
- 2008-10-31 AOL Hometown shutdown  by AOL.
- At least 14 million sites lost.  2002 stats estimate 14 million sites on Hometown that year.
- "Well it looks like AOL did it again. Another sneaky move. The Hometown pages all seem to have disappeared. [...] I only discovered this morning that AOL pulled the plug on Oct 31st, 2008." - taimantis.com, November 11th, 2008
- "Lots of information on AOL Hometown very important to people who put hard work into these efforts is being lost, possibly without notice." - David Dillard, "Meet the Googles" Visits the Grave Site of AOL Hometown to Ponder Its Past All to Short Life
- "I was surprised to find that AOL just shut down their homepage service on Oct. 31st. There were many great websites created through that service that simply no longer exist." - Dr. Jitters, November 12, 2008
- "I knew this was coming, I just didn't know the day. I tried, with the help of some great people, to get AOL to donate ficlets to a non-profit, with no luck. I asked them just to give it to me outright since I invented it and built it with the help of some spectacular developers and designers. All of this has gone nowhere. [...] I'm disappointed that AOL's turned its back on the community, although I guess I shouldn't be surprised." - Kevin Lawver, Ficlets Est Mort
- "A terrible thing happened recently. You might have missed it. AOL Hometown, which itself was actually a combination of a bunch of previously acquired websites, shut down. [...] It's all fine and good, those readers who sneer and say 'you get what you pay for' and 'ha ha, losers'. But the fact is, these people were brought online and given a place for themselves. Like a turkey drawn with a child's hand or a collection of snow globes collected from a life well-lived, these sites were hand-made, done by real people, with no agenda or business plan or knowledge, exactly, of how everything under the webservers worked. They were paying for their accounts, make no mistake – this was often provided to them as a tool combined with their AOL accounts. Some were absorbed from other companies as AOL purchased them. Some of these websites had existed for a decade. [...] We're talking about terabytes, terabytes of data, of hundreds of thousands of man-hours of work, crafted by people, an anthropological bonanza and a critical part of online history, wiped out because someone had to show that they were cutting costs this quarter." - Jason Scott, Eviction, or the Coming Datapocalypse 
- 2001 Desktop.com shutdown suddenly, without users being able to download their documents.
- ??? user profiles lost
- ??? user documents lost
- 2001 SixDegrees.com (wikipedia), one of the first social networking services
- 2000-07-02 PlanetAll shutdown by Amazon.
- 1.5 million user profiles lost including address books, calendars, buddy lists. (ibid)
- 2000-06-06 Amazon told users "PlanetAll.com will be going away"(ibid)
- 1998-08-04 Amazon bought PlanetAll 
- 1996-11 PlanetAll launched
- Wannadoo/orange personal sites
- Zooomr.com photo sharing / flickr competitor