Campaign_settings site rankings:

ad&d (36)
d&d (68)
tsr (24)
planescape (4)
frpg (5)
greyhawk (9)
ravenloft (3)
roleplaying (563)
forgotten realms (13)
taladas (2)
gnupg (2)
reading order (2)
outlands (2)
greytalk (2)
worldbuilding (2)
fantasy worlds (2)
netbooks (3)
living greyhawk (3)
neverwinter (3)
kender (3)
krynn (3)
faction (4)
raistlin (4)
gpg (5)
arneson (5)
remailer (5)
dungeons (74)
genres (954)
realms (6)
factions (6)

dungeons & dragons (30)

adnd (7)
jamis (11)