We're not a large fandom. There are only 20,000,000 people in the whole country, let alone fans! The average con is about 150 people - a natcon might - and I say *might* - get up to 500. Even the last Worldcon, back in 1999, was only 1500. So a separate filk fandom, if it exists, would be very small. It's informal, as I said in a previous post. If there are filk cons I don't know of them. I did once have a couple of not-very-good pieces in a filkzine, but that was years ago. We do have a lot of musicians who are just as likely to sing or play folk as filk. They do it at room parties and in the foyer in jam sessions and otherwise late at night. Once, we had a very nice music session at a room party for members of the Andromeda Spaceways Inflight Magazine co-op. Someone played the harp as we passed around gourmet chocolates and homemade cookies... I can't remember if we filked, though I am usually tempted, at such sessions, to sing "Banned From Argo" very loudly.
At Swancon, the annual Western Australian con, I heard Charles De Lint singing a song he'd composed about Batman; when someone pointed out that it was a filk song, he was horrified! (g)
I will have to ask one or two filking friends to visit this blog and add their comments to clarify.