I love Meta too!
I take a more cynical view on why it gets less traffic though. People (and I'm talking in general) want to be... meh, I can't think of the right word. Affirmation maybe? They want reassurance that people do indeed care about what they have to say. General gets the most posts, and that's why people post their stuff there, even when another forum is sometimes more appropriate. Of course, this leads to a self propagating cycle, as was mentioned before.
I think this is in part why people get upset when other people complain about OT posts - it's basically stating that people don't care about what you have to say. I also think that's why people don't bother to read Meta - less people here, and it's less of a feedback sort of forum, if you know what I mean. Less affirmation to be found here.
House Rules, Rules, Media, and Computers all work because there are enough people interacting in each forum to provide feedback. Furthermore, these four forums are even more feedback intensive than General. In addition, Media and Computers provide a place to talk about two common subjects that would be off-topic in General. Meta doesn't have that, for the most part.
So basically I believe people just want attention and affirmation that people like them - posting in a forum with lots of people in it, such as General, gets more responses, and thus more possible affirmation, and to a lesser extent attention.
But then, I'm also too cynical a lot of the time, so that's probably the extreme negative view.
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