I've been online since the 1980s, starting with BBSs and Compuserve. Following that were Genie, Usenet, and eventually FaceBook and Twitter. Of all of those, Twitter has been my favourite social media service. There's nothing else that comes close to it for following things I'm interested in, and of course, that includes science fiction and fantasy.
I use Twitter to follow authors I like: John Scalzi, Neil Gaiman, William Gibson, Elizabeth Bear, Mary Robinette Kowal, N. K. Jemisin, Paul McAuley, and several others. I am not sure what will happen to Twitter in the near future, though based on what's happened in the last couple of weeks, I don't think it will be good. I will be very sad indeed if Twitter goes away as it's been a big part of my life the last few years.
Andrew Liptak has a good article in his latest newsletter about social media, the infrastructure of the Internet, and the science fiction and fantasy fan communities. It provides some much-needed perspective on what's happening now with Twitter.
In particular, there's been quite a bit of introspection amidst the SF/F community, which has used Twitter as intended: an open square where we can talk about the books we like, shoot the shit, raise issues within the community, and so forth. They're understandably worried: Musk doesn't have a great track record with his online presence, and Twitter's long been a haven for trolls and bad-faith actors who stir up trouble, cause problems for everyone, and it doesn't seem like we have the best role model for dealing with this. Online communities are hard: there are a lot of things that go into it to ensure that users are protected and safe, and that bad habits don't get rooted into the community. The SF/F community has had an up and down relationship with Twitter over the years, but it's been a pretty constant thing, which makes this entire shift so notable.
I think it's safe to say that the Twitter that was around in 2009-2022 is gone, and what remains to be seen is what Twitter of 2022-beyond will look like. A social media platform is a tool like any other — it's just been a particularly useful tool for publicists, authors, fans, and everyone in between, which is why this feels like a real bookend to an era within the community.