I often vote things up if the person spent some obvious time and care in making a response whether I agree with the post or not. So no one should necessarily be reading any political affiliation into my nerd-it giving. If a person makes a good point or is informative even in a way I don’t want to hear, I usually vote it up. If I feel a post contributes greatly to the ensuing conversation, I might vote it up. I vote my own posts up if I really spent time on them. I wonder how Obama and McCain voted when they went to the polls on Tue Nov 4? (Ralph Nader I bet.)
I only vote stuff down if it is insulting, deliberately racist, vulgar or just plain mean. Or anti-nerd of course.

The nerdit system isn’t used as much as it was designed for. I wish people would at least vote for the content, (news, links, articles and blogs) even if they don’t bother with comments.