I think these projects focus way too much on platform building than content acquisition. The valuable platform is the one where the content is, whether that's celebrity feeds or professional networking. It doesn't matter how technically good your platform is if there's no casual reason to visit.

The early years of BlueSky were people talking about how it’s not Twitter.

People stick to a social network, and when they move is because they have big complaints about their previous home. If they didn’t, they would never have moved at all.

That’s probably the biggest lesson of the Web 2.0 era that everybody that tried to create a new social network had to learn.