WarioForums.com is the only place that I am sure I knew Wario's fans, I knew many people in the real world but I never knew if some of these people were or are Wario's fans.
Late as hell (as usual) but one of my uncles used to play WL3 a lot
my stepdad likes Wario a lot (although he's a lot saner than me when it comes into liking Wario...)
Or do you mostly only interact with the community online when talking about the games?
Personally I'm in the latter group. No-one I know offline is interested in this series, and even online, only a few people I know really care about it.