Sgt_Kickaxe - 6:30 pm on Feb 7, 2011 (gmt 0)
Lots of possibilities have been mentioned so far. One not mentioned, yet, could Moultano have been hinting at webmaster profiling? Some webmasters place adsense on quality sites, others make MFA sites. Websites, much like cars, are produced by various "manufacturers" and while some of those are known for producing top quality products others are known to cut corners (in one country or another).
Profiling webmasters might be a first step method to get an idea on the odds a site will be of quality or not. Give the benefit of the doubt to a manufacturer with a good rep, much like the credit industry does?
The question would then become "how is google measuring webmaster quality?".
Other ideas ?