"True" - because my current understanding (which Matt_Cutts can elucidate on if he chooses to) is that Google has looked into - but does not currently incorporate - the presence of advertising as a spam signal.
"Sadly" - because my independent research has shown that advertising - most notably the presence of Google AdSense - is a reliable predictive variable of a page being spam.
All things being equal, a page with AdSense blocks on it is far more likely to be spam. Yet as of a few months ago, that does not appear to weigh very heavily into the equation.
"True" - because my current understanding (which Matt_Cutts can elucidate on if he chooses to) is that Google has looked into - but does not currently incorporate - the presence of advertising as a spam signal.
"Sadly" - because my independent research has shown that advertising - most notably the presence of Google AdSense - is a reliable predictive variable of a page being spam.
All things being equal, a page with AdSense blocks on it is far more likely to be spam. Yet as of a few months ago, that does not appear to weigh very heavily into the equation.