I'm not familiar with the voting booth feature. But I do recall reading about voting in Applied Cryptography. There are ways to ensure that everyone has voted only once, without revealing how you voted. I suppose it's doing that: noting that the IP voted for =something= but not recording what. If you gave everyone a ballot with a serial number and a digital signature, then each ballot could only be used once, but that only opens up more problems, like how do you give everyone their ballots and how do you prevent people from selling theirs? That's no different from a paper-and-box election, though.
in reply to A little sugegstion about our voting booth
I guess tracking a dynamic IP is unfair to other people on your same provider, who might be locked out because you voted first.
Schniner concludes that there is no perfect and general solution that fills all the desired features.