Google AdSense Tracking Referrals
Google’s recent temporal and behavioral patent talks a decent amount about tracking advertising and site visitors. With AdSense they can also track the referrals which gives them another way to understand percent of market share and who your leading referals are if you display AdSense ads on your site.
their ad code shows:
google_referrer_url = document.referrer;
Google could likely use this data for their AdSense SmartPricing, fraud detection, and might even use it as an additional quality check on linkage data and sites.
If you link to a site participating in AdSense and nobody ever follows the link does that mean the link, page, or site could potentially have little to no value to humans?
If you have links from a ton of sites all using the same AdSense account could that be suspicious? If thousands of sites link to you and none of them dispay AdSense could that be suspicious?
It seems as though Google is trying to financially incentivize various webmasters in the concept of building its web of trust. Maybe it is part of the reason they don’t mind having shoddy sites in AdSense, as it helps them track relationships?
It is mind boggling how much traffic data Google has access to. WMW has a thread covering the topic of AdSense price based on referral data.
Aaron Wall is the Author of SEO Book