I find this interesting, it seems to indicate that everyone is moving towards the Fediverse. So, would an apt analogy be that it's going to end up being like a mall, with the mom & pop places on the wings and the anchors are like BlueSky, Mozilla, etc.? Also, what is AT Protocol vs. ActivityPub?

The report also distinguishes a Developer migration, and notes organizations that are currently working on providing ActivityPub integration, such as Automattic with WordPress, Flipboard, Mozilla, as well as other networks such as Threads, Tumblr and Post.news. No organization is talking about using the AT Proto network currently. This is why the report quotes Nilay Patel (from February 23), where he states that ActivityPub is where the app developers are. This seems to be holding up regarding companies and organizations, who are all focused on ActivityPub. Individual hobby developers seem to be a different matter though, where the AT Protocol seems to be of significant interest: the largest individual developer community for ActivityPub has less than 200 users, while the Discord for developers for AT Protocol has almost ten times as much, close to 2000.