Mirlo, which is similar to subvert, but a worker owned thing rather than a cooperative are dipping their toe into federation with more planned I think:

“…If you want your artist profile to be follow-able from other websites, you can now “Enable The Social Web” and people can subscribe to your feed from other places. With support from our NLNet funding we’ve finally enabled the ActivityPub standard integration on our site, so that people across the internet will be able to follow your artist account…”

Great to see so many open source ethical alternatives popping up.