http://www.complex.com/music/2013/09/50-hottest-rappers/
What we tried to prove is that by using Google Trends, there's enough raw data for you to draw conclusions about the popularity of different rappers (provided their names are actually something you can Google. So congratulations, or
condolances, to artists like B.o.B, The Game, Ice Cube and Nas for choosing monikers that prohibit us from accurately figuring out how popular they are on Google.) Our goal was to use Google Trends to try to get an objective, scientific ranking of just how "hot" the hottest rappers really are.

Basically they couldnt figure out because they have names that are similar to other things (A NAS hard drive, a video GAME,)
Which itself pretty much nullifies the point of even having this list if Complex themselves are admitting its not accurate