It depends. It takes more to form a community than a common descriptor. For example, consider "atheist". There isn't really an "atheist community", in that there's very little in common between atheist Buddhists, atheist Jews, former Catholics, apostate Muslims, atheist skeptics, atheist Unitarians, etc, etc.
There are many communities that are accidentally or intentionally atheistic, of course. But that doesn't mean there's a community of atheists.
Given both the Bitcoin and libertarian tendencies against centrality, I'd be really surprised to discover that there was really a single Bitcoin or libertarian community. I'd expect a number of relatively distinct communities that interact around common resources or interests.
As an example, consider the Great Lakes. There isn't really a Great Lakes community; people in Toronto and Chicago don't have much sense of shared identity. But the shared resource demands joint action, so you see things like this:
https://en.wikipedia.org/wiki/Great_Lakes_Compact
https://en.wikipedia.org/wiki/Great_Lakes%E2%80%93Saint_Lawr...