This is why for a new project I just launched I'm using pageviews as the metric (it's a pic sharing site) instead of voting up/down. Each IP address can only r

This is why for a new project I just launched I'm using pageviews as the metric (it's a pic sharing site) instead of voting up/down. Each IP address can only register one unique "vote" per 24 hour period. This makes the system still vulnerable to proxy servers and botnets, but it's not nearly to the point anyone would want to game it yet. (blacklists will go a long way against proxy server attacks)