Decius - 11:17 pm on May 1, 2011 (gmt 0)
A reliance on Google based software (Analytics, Chrome) is inherently flawed. It's like trying to calculate the quality of a site based on its alexa rank.
Also, for international and geographic searches it simply won't work because certain locales may be more prone to using one browser over another.
Finally, what if you don't use any google software? No analytics, no adsense, nothing on your site. And a non-chrome user visits your site. There is no data to be collected. I don't think this is a 10% thing - more like a 60% thing. And aside from the data you collect from what a visitor does once they are on the site, which is 90% of what is relevant to determining whether they found what they were looking for, Google will be in the dark with a lot of sites.
That being said, I'm not saying it isn't going to happen or happening, but Google can't expect results to be holistic if it relies on webmasters and users to use their software. Especially as MS and Yahoo are now encroaching on their search market share, their software usage will reduce likewise.
The big question is what do they do if there is no user data? Assume no one visits the site? Of course not. It's coin flip - if you allow google to track your site, they can see if it sucks or not. if you don't they have to rely on other factors.
Otherwise, clearly, they have to penalize you for not using analytics or adsense, or if your website is not chrome friendly. I don't know legalese, but wouldn't that be an anti-trust issue?