@atomicpoet From first glance, seems like they do handles slightly different. Instead of delimiting the user handle and the instance with an @, they blend it in with a period.
I see what they are doing there, they're making it so you can easily access a Bluesky account by typing a handle as if it were a URL. That's not a bad approach at all, and would be more intuitive than how ActivityPub services do it.
But the problem is, it looks too much like Twitter.