In this community, agreeing with a poster such as yourself signals me as sycophantic and weak-minded; disagreement signals my independence and courage. There's also a sense that "there are leaders and followers in this world, and obviously just getting behind the program is no task for so great a mind as mine".

However, that's not the only reason I might hesitate to post my agreement; I might prefer only to post when I have something to add, which would more usually be disagreement. Since I don't only vote up things I agree with, perhaps I should start hacking on the feature that allows you to say "6 members marked their broad agreement with this point (click for list of members)".