It simply turns out that some sites attract different followings.
Take a look at the GT forums for example, the site has double the amount of Sony fans then MS fans, and the Wii has barely any following there at all. People are complaining about the amount of Sony fans etc.
This site may appear to have a Nintendo Bias, (ioi even once had his name as 'Wii_Fan' I recall). Nintendo is listed first among the companies at the top(the only website I've seen that happen) and mods like Shams and Benkenobi have an open love of Nintendo. (And sometimes an open dislike for the other consoles.)
It's not that Nintendo has the most fans. But a large part of it might have to do with the age of all the hardcore Nintendo fans, who are in their late twenties-thirties, and are obviously going to have more interest in figures and statistics then your average twelve year old boy. Result: this site attracts them in droves.
Also because of extensive moderation, and the fact they are hugely outnumbered, It is my belief that many Sony and MS fans tend to tone down their fanboyism so as to stay on good terms with the others here.
Does the site have a Nintendo bias? No. The site is about representing sales figures etc. which are not twisted or changed in any way to suit Nintendo.
Does the community on the site have a Nintendo bias? Almost certainly. But that's basically unavoidable with the amount of Nintendo fans present.
