Measuring Searcher Utility

How does Google measure user utility?

[TIKii]

In my experience talking with folks at Google and interactions with Adwords - QS is less about CTR, position, CPC, landing page etc. and has everything to do with providing "Utility for the user" - If you provide it Google will give you a "Great" rating if you don't Google will rate you "Poor". All of the measurements people track are just indications of good/bad utility.

Anybody have any idea how Google measures ultility? I have often thought they look at the searcher's behavior. If a user searches for "blue-widget" and they vist ad #1 and quickly hit the 'back button' on their browser then Google may determine ad #1 to have low utility. If the searcher clicks on ad #2 and stays for an extended period of time or never hit their 'back button' then Google may determine the the site has a high utility and thus a high QS. They could track this using the Google tool bar?

Thanks for any insights.

[narsticle]

the length someone stays on your page is DEFINETLY a factor.