three things (aka my thoughts on yaoi)
1. There's a lot of crossover between Scans Daily and fic fandom. A lot of the content that gets posted here feeds the fic community. A lot of the comments here are indistinguishable from those you'd find on a fic comm. "Dick/Tim=OTP OMG!"
2. Franchise comics and tie-in novels are basically for-pay fanfic with some editorial oversight to prevent whacked out self-indulgence (in theory).
3. Posts that strip or change the context of scans are retelling stories, not just presenting them without an agenda. Putting together "Context Is For The Weak" posts, or epic scan series, is a fannish activity that has a lot in common with remixing, vidding or writing fic. (Not so much the "FOUR PAGES FROM BLACKEST NIGHT" posts, but yeah).