A fanlisting is "a place for all fans of a particular show, movie, actor, actress, singer, etc. to come together and build the biggest listing of people from all around the world who are fans of that subject."
This fanlisting takes it's name from a song by The Pillows called "Fool on the Planet." The Pillows did the soundtrack for FLCL but this song was not included (although there is an image of Haruko with a FOOL shirt). The title fits Haruko well in my opinion, and in some ways the song itself sounds like the relationship between Haruko and Naota (in some parts, anyway). The lyrics and translations can be found at Instant Music.