nostr:npub1cmgqvz7xr07euwkum3mjghjqcu4d3k2fcyf6g4uwwe5ggnd6fetq0wrzd2 nostr:npub1q8nhcxa8t9zfk06ggqwpwcr64znkxvnwt2wgzqdtga920g355p4qdfkct8 

As I understand it BS will allow self-hosting (own instance) in the future, but there is an index/lexicon - a means that accounts have to register with a central database by BS to become findable. The server software is not (yet) public, but could be recreated from the public protocol.

Twitter has CW for images.

M good at data protection, Tw less so, BS and Th a catastrophe. I don‘t believe that Tw, BS, Th meet GDPR, DMA, DSA, etc