Oh, how very strange... Lately, it seems MacPolls doesn't track votes by MacRumors username anymore (I stay logged in to MacRumors all the time at work and at home). If I vote in a MacPolls poll at work (regardless of whether or not I'm logged in) I can vote again at home. I'm guessing something was changed in the MacPolls system because I used to have problems with the poll thinking I had already voted when I in fact hadn't yet voted (the zero vote problem). Now, I've got the exact opposite issue (the double vote problem).