Only one, I was tempted to sign up to another but I only just about got a nice mix of subscribed communities on this one and don't have the patience to go through it again. I don't really see the point, either, unless you are signing up to a second one that isn't federated with your current one.

Also, shout out to ReddThat.com, absolutely zero glitches or issues so far except for those that seem to be fediverse wide. Good place to be with good people.