It's not perfect if you're worried about people voting more than once. We tried doing an office poll about something people held strong opinions about -- what video game to bring in for an office tournament -- and within twenty minutes, coworkers had rewritten ballot stuffing scripts in bash, PHP, and Python.
Not to mention that you can submit multiple votes by opening the page in an incognito window in Chrome.
Not to mention that you can submit multiple votes by opening the page in an incognito window in Chrome.