Bluesky, a decentralized Twitter-like social network, is pausing new signups “temporarily” to try and resolve performance issues it’s been experiencing after Twitter introduced limits on the amount of tweets you can see in a day. Even though you still need an invite code to be able to join Bluesky, it seems that the influx of new users has been a problem.
It's unfortunate that this drop in replacement isn't in the fediverse though. Bluesky's success isn't technical (yet), it is better marketing and connections with VIP users.