Hashtags have fallen out of use on Twitter, so not sure that's the key, although...

3cats-in-a-coat 10 months ago | parent | context | favorite | on: Threads 24% likely to overtake Twitter, down from ...

Hashtags have fallen out of use on Twitter, so not sure that's the key, although having "rooms" of some sort would've been useful. They should iterate on it. So far it's not quite there, but I hope they evolve it fast to meet needs.