According to alexa "daily reach", traffic from Mar 2009 to Mar 2011 went from reach ~0.0137 to reach ~0.104, so I scaled the Alexa graph to show ~7.9x more absolute uniques in the end than in the beginning.
Thanks for the comparison, I'm actually very impressed by the accuracy of Google trends.
I wonder given the lack of accuracy between quantcast/alexa/compete if there is room in the market for another traffic intelligence site that piggybacks off of Google trends somehow.
http://i.imgur.com/T1H1C.png
Google is actually pretty close, although the last few months are off.