A partial response to Marty and yet further interesting thoughts on what the term "webmention" has come to mean, and what the technology could become.
Webmention-as-reaction is fine, but it’s very difficult to get good UX with webmention-as-comments. Reply chains are difficult to follow, especially if one of the links in the chain breaks
^ that, in particular, is something I've been thinking about a lot lately with my own implementation. I think I'm coming to the conclusion that Webmentions are fine to support, but maybe aren't a good replacement for actual native comment systems. Then again, with static sites, native comment systems create their own headaches.
Fluffy (as ever) also raises some useful points around community moderation and the potential for abuse.