Unfortunately, I have trouble finding details about their approach except through paid subscription to wsj.com If anybody knows more about Quantcast or their a

Unfortunately, I have trouble finding details about their approach except through paid subscription to wsj.com If anybody knows more about Quantcast or their approach (or has read full article), maybe you could let us know if what they're doing can teach us anything? [ see also: http://www.quantcast.com/target.com http://www.quantcast.com/target.com ]