Eric, I think it would be a great idea to create user accounts. It might enable you to try online polls too, with user accounts the results won't get skewed. Good luck

We actually did run polls for quite awhile, back in the late '90s.  We had basic checks in there to prevent the same IP address from voting too often and we weren't seeing too much apparent skewing, but people did take them very seriously and tended to e-mail us and even call in (believe it or not) if the results weren't favoring their own pet opinions.