Webmention is a W3C web standard for decentralized comments, reposts, and other interactions across websites. It’s basically like a ‘pingback’ with some other building blocks for things like federating identity.
Setting it up is a little clunky to do by hand, but it looks like most people use plugins for their hosted blogging CMS (e.g. WordPress). There are other centralized aggregators that manage webmentions going out and in, but that seems antithetical to decentralization.
One challenge is setting it up for static websites–webmentions result in a POST request that need to be handled and persisted by your server if you want to do anything with it e.g. display them as comments on your blog post. One approach is to use some other service to handle the request and store them in static files (like text files in a git repo), but this also means additional complexity and exactly once processing is difficult to get right (I imagine webmentions have a ton of duplicates that need to be handled somewhere).
See also:
- IndieWeb is an organization and community that supports the adoption of webmentions and extends microformats for things like login with your personal website (IndieAuth).