Spak, you're right, somehow I missed the point that if it gets posted, not only would Nintendo have seen it but then the rest of the world does and then we'd have a real indicator of how many Wii owners want something. (Then again, someone could vote six times, but still.)
I remember when we discussed if Nintendo could access our play history from our message boards, but now we don't really know. However, a poll is certainly handy for Nintendo to track what we like.
Given the Wii's "new gamer" philosophy, questions about the Wii or games itself might be intimidating. However, if they were in a category all their own, it would be okay. However, they might think that people would take it as a sign that Nintendo would necessarly do something to appeal to the popular choices, so then they'd probably put up a disclaimer if people did take the questions too seriously or felt that Nintendo wasn't.

There's always some trouble. So instead we're getting simple and innocent questions like if you like dogs or cats. Then again... Nintencats, anyone? (Or Kittendo, whatever.)