I've setup a new Mastodon server on mastodon.online. The idea is to provide another space for people who would've landed on mastodon.social but can't because it's closed.
Even though I am currently in charge of both there are still logical and infrastructural separations between the two that give this move meaning in the context of decentralization.
Not to mention I've already scaled to mastodon.social's size once, so it would be easier for me to do again than to scale mastodon.social further.
I will undoubtedly need new moderators for it if it catches on in the same way mastodon.social did. Though I don't know if it will, since mastodon.social's initial break-through and subsequent snowballing was down to a lot of luck.