@trinsec email is a federated service, with many small players and a few big ones, eg Gmail, Hotmail/Live/Outlook, etc.
The fediverse is federated social media, where even the largest are small. If Twitter supported ActivityPub - i.e. accounts can directly follow twitter accounts and vice-versa that would be good.
It would also be the largest instance by a long way.
@sgryphon Ah, on that bike.
I think a fair amount of instances are going to block twitter then, lol.