The Verge has an article on how the alt-right is using Mastodon as their social network of majority.
On a related note, I've migrated my own account to a different instance for partially unrelated reasons. If your follow hasn't been transferred automatically because you're on an outdated instance, please, re-follow manually.
Not like I'm planning on posting there that much. But, y'know, just in case. Don't want to be screaming into a void. :)