[balanceiskey15]

I don't know about Twitter itself, but I think there have been a few attempts at federate competitors or protocols. The most recent I can recall is Tent: https://en.wikipedia.org/wiki/Tent_(protocol)

It seems like Tent has morphed now into this: https://cupcake.io/

[zanny]

GNU Social is probably the most famous open twitter competitor and it uses ostatus:

https://en.wikipedia.org/wiki/OStatus