Comment by bohm

I don't expect it to stay closed source. But there are significant differences to Mastodon. Just to give one example: Mastodon server admins actually can read your private messages. Also Blue Sky's approach to data portability and how to implement filtering/indexing is more developed. It might be personal preference, but I prefer AT Protocol's approach where the servers have less powers, and the users have more power. A lot of little design decisions add up to a qualitative difference.