Sending Webmentions to other sites seems like an insane thing to turn down. Your blog software sends a simple message and now that blog can know to link back to you. (And go ahead and send pingbacks, too—way too easy.) But a site like this one, Lobste.rs, where there is a lot of discussion about a given link—seems even better, more advantageous, generally, usually, to bring the author in.

Now imagine if this continued:

• Send a Webmention (u-syndication style) to https://lobste.rs to submit a link.
• Send a Webmention (u-like-of style) to a lobste.rs page to upvote.
• Send a Webmention (u-in-reply-to style) to a lobste.rs page to comment.

And you could verify these Webmentions (and attach them to a user) by verifying that the Webmention source is listed in the user’s ‘about’ section.