The last #Twitter exodus had people joining mstdn.social.
This one has people joining mas.to.
For this last one, I wonder why the users all picked mas.to. mstdn.social made sense, many of the users were Indian and that's a majority Indian instance.
@dave There isn't any documentation of this in the about page, but it was widely known that mstdn.social was an India-friendly instance and @stux took great strides in accommodating them.
https://qz.com/india/1746734/angry-twitter-india-users-are-migrating-to-mastodon-in-thousands/