
Google made a stealth announcement on December 7: the rollout of personalized search results. Google will now track individual search behavior for 180 days via cookies (previously held for 30 minutes) and feed historical site clicks into all new searches, regardless of whether you are logged into a Google account.
The implication is that Google search results will be increasingly different on individual browsers. To respond to this change, we’ll plan to evolve our SEO success measures to look at traffic and conversion in addition to cookie-free search rank results. I’m in the process of updating relevant guidelines.
A history-free rank order can still be tracked, but you might have less data on its percentage of total. New queries become more important because follow-on Google responses are built from previous click choices. Being #1 won’t mean as much; traffic & conversion become more relevant measures than rank. For known brands, I would expect to see more qualified SEO traffic over time. Less preferred players will probably spend more on paid search, which has fewer personalization rules.
More details:
· Google universal personalized search announcement (Google)
· A more in-depth review & detailed instructions on opt-out (Search Engine Land)



