What kinds of groups are there? Given the lack of popularity and commercial support, combined with the complexity to connect a client with an available server

What kinds of groups are there? Given the lack of popularity and commercial support, combined with the complexity to connect a client with an available server (compared with downloading an app from the store), I'd expect that they are populated mostly by old tech people or passers-by from universities; and any special interest group would have small user base coming from that demographic profile. Are my assumptions correct?