Hm. Interesting question. To be honest, I don't tend to process the difference too much; they all register as the same thing in my mind. Personally, I use fan fiction as a tag and on my archives, but mostly just use fic to describe what I'm writing (the occasional fan fic has slid in, now that I'm looking). I also consider fanvids to be one word, but fan art to be two. I'm not sure why.
no subject