Thanks @mackuba, great data. Yes, Mastodon's MAU are logins within the last month so it's apples-to-oranges, still very interesting to see.
I'm curious what will happen when they open it up. Back in the day Google+ was amazing with a few million people in the beta, and then it wasn't so amazing, but Bluesky has better moderation functionality and a lot more diversity that G+ did when they opened it up so we shall see.