What is a Fanzine?

I pointed at this posting on SF Awards Watch yesterday, but I think it bears repeating because the comments have gotten into something I thing interesting, and that is the question of "What is a fanzine?" When I suggested that individual blog posts could be considered as "issues" of a fanzine, one person said that she wouldn't even consider a particular fanzine that has won multiple Best Fanzine Hugo Awards (not counting those won by its editor and primary writer) as actually being a fanzine at all (presumably it's not a semiprozine, either, but that's neither here nor there for this purpose). I'm intrigued by this; it shows just how subjective the definitions are.

Comments are again disabled becuase the discussion is better done over there IMO.