You’ve created a personal site and started adding microformats: great! (“h-feed” readers are now able to recognize your post types, avatar, and so on.)
Onto the next step: Webmention.
Webmentions are a lot like the pingbacks of yore. They let authors of other sites now that you’ve mentioned (or replied to, or liked, and so on) one of their posts.
If their Webmention endpoint is able to parse microformats, it, too, will recognize your (source) post’s type, creation date, and more.
IndieBlocks comes with a basic Webmention implementation. When enabled, it’ll attempt to notify linked pages, and allow other websites to do the same.
Incoming webmentions are turned into regular WordPress comments, and treated as such.
Avatars, when enabled, are cached locally.
Outgoing webmentions, by default, are sent just once. They’re sent in the background; it can take a few minutes before the target site receives them.
If after updating a post, you’d like to resend webmentions, let the linked pages know you’ve made some changes, it is possible to do so.
If you’re using the block editor and the Webmention panel is not visible below the post editor, click the “three dots” in the top right corner of WordPress’ admin interface, then Preferences > Panels, and under Additional, ensure the Webmention toggle is active.
In the classic editor, expand the “Screen Options” near the top of the screen, and look for the Webmention checkbox.
The Webmention panel contains a list of webmentions sent before, and a “Resend” button.
Currently, no webmentions are sent whenever a post is deleted.
Incoming webmentions, too, are processed asynchronously, and can take up to an hour to actually appear inside WordPress’ admin interface. Invalid or duplicate mentions are discarded silently.
For outgoing webmentions to work as intended, your site’s front end should include so-called microformats. Put simply, microformats are “the simplest way to mark up structured information in HTML.”
In a WordPress context, that means both the HTML for the overarching site (as laid out by your “theme”), and that of your actual posts should have some microformats added to them.
Luckily, IndieBlocks does both! (See also: Theme Compatibility.)