I only became aware of the existence of 'filk' quite recently, due to Piers Cawley's Friday night song-swaps on YouTube.

Filk intrigues me, as a diehard folkie who is also into some scifi and comics.

What specific subjects are biggest in filk? I mean, are there some particular subjects (or movie franchises or book series) that really stand out in the filk world as massively popular?

I was also wondering who is really good in the filk world? Who is the filk world's equivalent of a Martin Carthy or Bert Jansch? (The few filk acts I've listened to so far have been pretty uninspiring frankly)