Interactive Romney Approval Tracking Poll

Courtesy of our opponents at Blue Mass, I came across this wonderful graph tracking Mitt Romney's approval ratings (SurveyUSA results). I could spend a couple hours playing with the variable demographics, and trying to analyze them. I may indeed do this at some point, but for now I'll leave it to your enjoyment. (I might make a permanent link on the sidebar to this poll)

Note: what does anyone know about reliability/skew of SurveyUSA?