2ch is a general bbs that is more or less the center of Japan's internet community and is big enough to have a hit series (Densha Otoko) based off it. Comparing that to gaia, which caters to a section (the dirty fag section) of English-speaking anime fans... I think the difference in traffic between the two sites should be even greater.

Or at least, there shouldn't be that many English-speaking anime fags out there.