A: SocialPredictor is similar to SocialPredator which is what I thought when I first read it.
B: "You must be logged in to use this feature!" = Fail.
I won't touch on the name so much, but there is a much better way to approach the login issue. I assume that logging in is only to keep the votes uncontaminated, but you said that you wanted to make this site more fun than statistically valid, and seeing the login requirement was not fun for me.
Later impressions:
This site has the potential to be an interesting/fun way to spend some time, and if I could A: see the predictions before voting (ie. just being able to browse and see what most people think about a specific subject), and B: not have to log in except maybe to participate in a discussion afterwards, then I would be very likely to use this site as a way to pass some time.
Also, a thumbs up for having a "correct users" section. I think the possibility of getting the predictions "right" and being able to be respected everywhere (on the site) as an accurate predictor is another fun angle that will attract and keep users.
Final impressions:
This is a startup, and by definition is designed to earn you money. Is there a plan for this in the future? Do you think ads are the way to go, or maybe sell the results to marketing agencies (for targeted subjects and users)?