More realistically, though, i honestly think it has to do with the subject and focus of the site more than anything. Afterall, it's not terribly surprising that a writer for adult fantasy (not like erotic-style, but like not teenage twilighty stuff. Like thick, 1,000 page epic fantasy books) has more well-read fans who are capable of coordinating themselves like adults.
Also probably has to do with community size as well. We aren't exactly huge here, which helps control the atmosphere a bit better. If there was thousands of visitors and posters every day, i'm sure we might have a bit more issues.