The latest announcement from Twitter is that the site is going fully pay-to-play -- to be in recommendation feeds or even vote in polls, you will need to be a subscriber. [1] While it remains to be seen whether the site will follow through, these plans are consistent with the relentless promotion of a subscription-based model under the company's current leadership.
While new alternatives are launching every month, Mastodon remains the primary place folks are migrating to. This Dewey Square report is a good read on recent developments, including the Mozilla Mastodon instance, the Medium.com one (which is rapidly closing in on 10K users), and the Flipboard one. https://www.deweysquare.com/wp-content/uploads/2023/03/DSG-Snapshot-of-the-T...
Being open source and community-based, Mastodon should be a perfect fit for Wikimedia, and I still very much hope that Wikimedia Foundation will set up an official presence in the fediverse, much like many chapters/affiliates already have.
Warmly, Erik
[1] https://www.theverge.com/2023/3/27/23659351/elon-musk-twitter-for-you-verifi...