"When you link to a website, you can send it a Webmention to notify it. If it supports Webmentions, then that website may display your post as a comment, like, or other response, and presto, you’re having a conversation from one site to another!"

https://indieweb.org/Webmention

I am glad someone else asked this. It seems terribly explained. A picture or video might do well here.

From the explanations below, I think the person who gets mentioned will receive a notification (email?) from webmention.io (Both people(domains?) have to be registered on webmention.io)

"Webmention[1] is a W3C recommendation that describes a simple protocol to notify any URL when a website links to it, and for web pages to request notifications when somebody links to them. Webmention was originally developed in the IndieWebCamp community[2] and published as a W3C working draft on January 12, 2016.[3] As of January 12, 2017 it is a W3C recommendation.[4] Webmention enables authors to keep track of who is linking to, referring to, or commenting on their articles. By incorporating such comments from other sites, sites themselves provide federated commenting functionality."[1]

If you want to know a little more about how this fits in with other adjacent social web protocols, I'd recommend the Social Web Protocols document[2].

[1] https://en.wikipedia.org/wiki/Webmention

[2] https://www.w3.org/TR/social-web-protocols/#delivery-mention...

See the link in ivan_ah's comment: https://indieweb.org/Webmention

"When you link to a website, you can send it a Webmention to notify it. If it supports Webmentions, then that website may display your post as a comment, like, or other response, and presto, you’re having a conversation from one site to another!"

"Webmention is a simple way to notify any URL when you mention it on your site. From the receiver's perspective, it's a way to request notifications when other sites mention it."

https://www.w3.org/TR/webmention/

Sounds pretty similar to pingbacks

Have you ever used twitter? There is a notification when someone answers or retweets a tweet of you. Webmention is basically this notification, but decentralized. Someone responds to an article of you and sends you a notification where you can find it. You then can shiw this under your article and respond back and allow your readers to read all this.