A like is nothing more than a way of saying, "I like this". Think. You can come up with a way to do this that doesn't require you to abandon RSS (read: Atom).
If Alice posts something and Bob likes it, then he can say so—from his perspective, he clicks "Like", and in turn this just ends up as another entry in his own feed. He doesn't need write permission to anything on Alice's server, and Alice doesn't need a smart (social protocol-aware) daemon sitting on the line listening. If Alice is subscribed to Bob's feed, then she's already lined up to get it. If she's not subscribed to Bob's feed (and maybe even doesn't know he exists) but is so neurotic/insecure that she craves validation from strangers on the Internet after years of conditioning on Facebook, Twitter, Reddit, and HN, then she can subscribe to Marge's feed. Marge is Alice's friend. Marge casts a wide net (follows a lot of people) and keeps an eye out for anyone saying they liked Alice's shitposts. When she notices, she lets Alice know: Marge squirts an entry into her own feed saying, "hey, Alice, look over here at Bob saying he liked your shitty Beetlejuice tribute" (which is pretty much exactly the mechanism behind boosts/retweets—except these would be boosts/retweets not of content but of what is known at least in the XMPP vernacular as "presence" information). Also, Marge is actually Facebook/Google/whoever, once they realize how lucrative it is to have this kind of influence and mandate in the next generation of social media.
Previously: <https://news.ycombinator.com/item?id=30862612>
