Voting goes as follows:
Before we were ranking in list form, downvoting if a player was ranked too high, upvoting if the player was ranked too low, but we got a lot of complaints that it was a little convoluted. So from now on, if you think a player had a good game, thumbs up! If you think a player had a bad game, thumbs down!
For evaluation check the game's analytics, and take a look at the boxscore.