I have a website where you can vote things up and down. There is no login required to vote and it should register that you have already voted on a particular thing you have already voted on the next time you visit.
It seems to work fine but some times it allows me to vote again on some things. The way I am *trying to* prevent people from voting twice is by logging their IP address and setting a cookie on their computer. I know this isn't the best way to do it, as cookies can be cleared and IP's can be dynamic. So I am asking you if you have ever ran into a similar problem or know another solution to prevent people from voting twice. I want user registration to be a last resort.
Thanks a lot guys,