This article is a stub. You can help the IndieWebCamp wiki by expanding it.
Posts and variants are perhaps the building block of an indieweb site:
Stuff in/of posts:
The ability for one webpage to let another it has linked to it is a vital indieweb building block. Amongst other purposes, it helps software pass SWAT0.
The ability to use your online identity (domain) to authenticate yourself on the web.
A web action is the interface and user experience of taking a specific discrete action, across the web, from one site to another site or application.
A link preview is what various social network silos (e.g. Facebook, Twitter, Google+) show underneath notes and comments that have one or more URLs, by extracting information from those URLs content and showing a title/summary/photo for those URLs underneath the posted note/comment.