atproto is like if you could post tweets to your own website and then twitter would be able to draw in all the tweets from across the web into a normal-looking social app
yeah our ELI5 is "what if yr website IS the data source and every page had its own API". We had a microblogging demo on Glitch which we haven't reposted since Glitch went down, but our working title for microblogs on OP was "oofs" since it's another synonym for hashtag. "Tag me in yr oof!"