Originally Posted by Prime Junta 
Might be a good idea to record the IP number of the votes. Combine that and the times, and you'll get a system that would be pretty hard to game. You'd need a botnet or something…
Even then I could vote from work and from home as a guest. I think a poll should be only accesible for members. It's not that you have to share your whole live here when you don't want too -> Make a gmail address and it's done.