Re: A Song of Ice and Fire books
I think the fanfiction mention was meant to indicate novels within the world of ASOIAF written by someone other than Martin. Shared world novels, such as the various dungeons and dragons novels or tie-ins like the Star Wars EU, are frequently referred to as "fanfiction."
"..the mere intimation that there might be more to a heroic narrative than the heroes are the Good Guys, the villains are Bad Guys and the heroes should Win a rousing Victory appears to be in itself such an offensive contention that it arouses a kind of defensive knee-jerk hysteria just by surfacing." - Richard K Morgan