There is a skeptoid episode[0] from 2011 that overviews the different types and some of the science behind it. And, it even mentions the difference between a vo

There is a skeptoid episode[0] from 2011 that overviews the different types and some of the science behind it. And, it even mentions the difference between a voting system and a ranking system. [0] http://skeptoid.com/episodes/4281 http://skeptoid.com/episodes/4281