Previously, we only offered Personalized Search for signed-in users, and only when they had Web History enabled on their Google Accounts. What we're doing today is expanding Personalized Search so that we can provide it to signed-out users as well. This addition enables us to customize search results for you based upon 180 days of search activity linked to an anonymous cookie in your browser.
That is a pretty big shift, which is going to make a lot of waves/noise in the search marketing circles.
I'll be watching my referrals, but I don't really anticipate that this is going to have a big impact on my sites organic traffic. Maybe even a good thing.
Regardless, google deserves a
for their rollout of this one, imo.