A Webmention enables enables cross-site conversations. Letting site A know that site B is mentioning them (be it via link, a like, a re-post... there are many times of mentions).
One of the cool use cases is to link your Fediverse account (Mastodon, in my case) with your blog. So every time you share a link from your blog and people react to it, these reactions (comments, or likes) will show up as native comments in WordPress. Pretty cool, huh ? 😁
Requirement: Enable pingbacks
There are 2 things you should enable in Settings > Discussion
- Attempt to notify any blogs linked to from the post
- Allow link notifications from other blogs (pingbacks and trackbacks) on new posts
Otherwise even if webmentions hit your site, you wouldn't see them.
Requirement: Install the Webmention plugin
This free service is used to ping your site when, in my case my Mastodon account, makes a post linking to one of my articles. The likes and mentions from that initial post on Mastodon will be pinged back to my WordPress site.
Requirement: Install Semantic-Linkbacks
It modifies the way your comments are printed, adding the mentions, likes in a nice way. It includes CSS and JS for these rich features.
It might need a little tweaking to show the comments to your liking, if the out of the box doesn't please you. A part from that, quite straightforward.