The OP link is to a very much alive mastodon instance… so yes its doing fine. No idea about Threads but apparently some people use it.

But your claim is that twitter is no longer the center and many niches have migrated to Mastodon. I highly doubt this, unless you can point out an actual niche where Mastodon has more active discussions than twitter.

My claim is not "many niches migrated to Mastodon", but "Twitter is not at the center of tech discussion". At least, not for the hacker types. Even here, the majority of HN links that show up as a Twitter thread are about technology "businesses", not tech itself.

I don’t know how you can say that. The whole fiasco with open AI recently was a good example of how Twitter was the place where you could really stay up-to-date with everything going on. All the main players were posting there.

I love HN, but just because there wasn’t a lot of links to Twitter doesn’t mean it’s not the center of tech discussion

Do you care about the channels used by the "main players" to broadcast their message, or where the conversation about the events were happening?