Adding h-entry to your post pages enables post information discovery on your permalinks, which is useful for a variety of things, including:
Adding h-entry to your home page enables:
By using a microformats2 parser, and looking for h-entry items, your code will automatically get both h-entry and classic hAtom post information from people's post pages and home pages, which are published in total in combination by a double digit percentage of the web (thanks to WordPress default templates including such markup for 5+ years), and especially cutting edge IndieWeb sites.
HTML on a page is historically more accurate than feed files (see that page for more details on why).
Thus for the best user experience, your consuming code should first consume the h-entry (and by backward compat of such parsers, hAtom) of pages before looking at secondary side files.
How to publish
Use h-entry to markup:
h-entries will typically be used in two places: alone on post permalink pages and in plural on feed pages. On post permalink pages they should be a top-level microformat (not nested under anything). On feed pages they may also be children of a h-feed if you wish to add feed-level data like feed name, author.
How to consume h-entry
For how to consume feeds of multiple h-entry posts, see How To Consume Feeds.
To consume a single h-entry:
For each h-entry, regardless of whether they’re being treated as a single post or part of a feed:
See also the processes documented on comment for handling incoming comments, updates and deletions.
move general processing
Many of the processes documented on comment (e.g. deletion) can be applied equally to other cases of h-entry consumption (e.g. in a reader), and some of the detail given here applies to comments processing (e.g. datetime processing). Anything which is applicable to general h-entry processing should be moved here, leaving only anything specific to the comment use-case on comment, and these algorithm referred to from there --Barnaby Walters 05:33, 9 June 2014 (PDT)
bad hentry properties
Some h-entrys encountered are missing a "content" property and have just the implied "p-name" property which end up with an inappropriate value for the name. These URLs were sent via pingback to a blog post on aaronparecki.com, and are hEntry posts rather than the microformats2 version.
Pretty much everyone on the IndieWeb publishes h-entry because it is a fundamental building block for the richer UX of Webmentions of federating and displaying comments, and showing higher fidelity reply-contexts on reply pages as well.
E.g. see people's personal sites linked from irc-people.
What uses it
Numerous projects and sites are parsing and consuming h-entry for various purposes, including:
In short, h-entry is the key building block for the indieweb. It represents a unit of content, to be syndicated, for a variety of use-cases.
Requests to add h-entry support. Both publishing and consuming code.
Requested consuming code