@ChrisPirillo My suspicion is because ActivityPub is server-to-server, and subsists by writing to 1,000s of servers.

AT is more convoluted. It’s personal data to big graph server to Labeller / App View / Feed Gen.

Why?

Well, my suspicion is that Twitter wanted to avoid liability for all the crazy stuff being posted there.

Twitter didn’t want to be a publisher.

They wanted to be the Google of self-hosted social media posts.