Every schoolkid in Germany seems to be using them. They even come in the cheap pen cases you can buy at the supermarket.
I don't know if this is still accurate, but during my time in school (finished in 2009) we had to use fountain pens from grade two and most teachers stopped caring what we were writing with in grade 7. From that point on most of use used ballpoint pens.
Huuuge communities online exist though. You might be surprised - check out fpgeeks forums or fountain pen network - both forums list local gatherings and pen shows.
Reddit's /r/fountainpens, too. There's an IRC channel that's fairly active, but I don't have the server address in front of me.