Nintendo gets a lot of love as well as a lot of hate

Yep, the Nintendo gamers are the majority here.

50% = Nintendo Gamer
30% = Playstation Gamer
12% = Xbox Gamer
8% = PC Gamer

I agree with all the points that others here have brought up, and I still would not be surprised if the majority of users were Nintendo fans. However, there is one important point that nobody has brought up yet:

Nintendo hardware is supported by Nintendo software. What does this have to do with what we are discussing? Let's say you want to talk about Assassin's Creed. You wouldn't put your thread in any subforum of the big three, because it is a multiplat. So even if each console had a third of the VGC users, Nintendo Discussion would be the most active, because the PlayStation and XBox users play mainly third party multiplat games, so they place their discussion in Gaming Discussion.

i don´t know, maybe nintendo is controversial

Nintendo's a hot topic. Lot of hate threads, lot of positive threads, and a lot of news gets posted as well.

A bigger sample over one month gives these numbers.

Nintendo - 360 threads.

Sony - 160 threads

MS - 45 threads.

A bigger sample over one month give these numbers:

Nintendo: 360 threads. 

Sony: 160 threads. 

MS: 45 threads.

EDIT 

NintenDomination about 500 posts in a month

Playstation Nation abot 500 posts in a month

Xbox Empire about 3000 posts in a month

Nintendo is more interesting.

You are a part of everything.

Um, I actually have a good answer to this. Nintendo discussion is really focused in Nintendo Discussion. While Sony discussion can be both Sony or Gaming Discussion.