Google Adwords Quality Score is perhaps the most talked about subject in PPCLand. It’s one we’ve spend a lot of time writing about over the past few months. In this new video, Google’s Chief Economist, Mr. Hal Varian, provides a great overview of how Quality Score works in practice in the ‘Ad Auction’ which controls when, where, and for how much your PPC ads are displayed on Google. This is absolutely must-see online video for anyone managing paid search campaigns. No matter how much or little you know about QS, this video is worth your time.