Like, i’m thinking photo album sharing (twitter-like makes photos ephemeral, quickly disappearing on the timeline) and conversation (twitter threading has never been strong imo).
As for actually doing this... running a PDS and relay isn't that hard, and the red dwarf web client is online and can be configured to point to whatever appview you want. There's significantly less experience running your own appview, but there are options & folks are happy to help.
I no longer recommend ATProto, in part because the public by default was a terrible choice. People prefer privacy, not anyone in the world able to read all of their activity. Bolting permissioned buckets on after the fact is not the way, it needs to be core to the protocol design.
Example: https://freecities.app
Video demos: https://vimeo.com/1141492621/23e8b84b8b
Disclaimer: I built it. Lovingly, over 15+ years.
https://www.noemamag.com/the-last-days-of-social-media/
Seems like it maybe suffers from the "fiefdom" / portability issue that other platforms struggle with, but I haven't looked closely.
In this case, pumping around information so social networks appear to be one unified system is a good thing because you don't have to visit them all to check if there are new posts, etc. and you can avoid getting caught in an algorithm.