Yes when we were standardizing Webmentions we all knew that. Personally, because I got started coding in 2005 around the time they became popular for blogs (htt

Yes when we were standardizing Webmentions we all knew that. Personally, because I got started coding in 2005 around the time they became popular for blogs (https://www.hixie.ch/specs/pingback/pingback https://www.hixie.ch/specs/pingback/pingback), but 'pingback' isn't always well defined (by one nonprofit org's IP), it involves XML-RPC (while form-urlencoded works fine and is simpler for limited scope), and the W3C Social WG charter read as somewhat instructive to prefer JSON or form-urlencoded encodings to XML. https://www.w3.org/2013/socialweb/social-wg-charter https://www.w3.org/2013/socialweb/social-wg-charter Somewhat similar story with how 'WebSub sure looks a lot like PubSubHubBub' https://www.w3.org/TR/websub/ https://www.w3.org/TR/websub/ https://pubsubhubbub.github.io/PubSubHubbub/pubsubhubbub-core-0.4.html https://pubsubhubbub.github.io/PubSubHubbub/pubsubhubbub-cor... Or how "ActivityPub targeting and delivery sure looks like Linked Data Notifications" https://www.w3.org/TR/activitypub/#h-note-9 https://www.w3.org/TR/activitypub/#h-note-9 https://www.w3.org/TR/ldn/ https://www.w3.org/TR/ldn/