The Dark Side of Google's Personalized Search
Last week Google announced it would roll out Personalized Search worldwide, and turn it on by default for all users who don't explicitly opt-out. As most users won't understand nor care to opt-out, this means the vast majority of users will start seeing personalized SERPs.
At first glance this seems like a good thing for users. We ought to be getting more relevant results adapted to our website preferences and search behaviour.
On the other hand, everything we search for will be stored for at least 180 days (if not logged in to your Google account - if you are then it's stored until you manually delete it). That's not to say the data disappears after 180 days, just that Google stops using it for personalised results.
Google says it has strong privacy safeguards in place to protect search history data from abuse, but their track record on privacy hasn't been what we'd call exemplary. Only recently the Google CEO Eric Schmidt said that if you were doing something you wanted to keep private you maybe shouldn't be doing it at all. This mind-bogglingly ignorant statement serves to demonstrate the breadth of Google's disregard for privacy and its utter failure to understand its importance.
Another example is Google's stance towards IP addresses. The search giant considers an IP address 'non-personal data' and thus not subject to any kind of privacy. Unfortunately the legislation in many countries disagrees with Google, as there are countless examples of users accused and convicted of copyright offenses based on little more than their computer's IP address.
Privacy issues aside, for SEOs Personalized Search is also a big deal. Already with the integration of universal search, real-time search, and local search into the SERPs, the concept of ranking is losing its meaning. Now with Personalized Search it's possible, even likely, that every user will see different results. Your site may rank 1st for some users, 5th for others, and you'll be none the wiser.
That is, until someone figures out a cool Google Analytics trick to report the exact rank - so far we can only get the page the result was on.
That's not to say that SEO will become irrelevant, just that basic rankings no longer suffice as the key metric for SEO success. New metrics will have to be adopted to measure the effectiveness of your SEO efforts, and the full impact of Personalized Search on the search marketing industry has yet to be fully gauged. It'll take some time before we will understand how this global roll-out of Personalized Search affects SEO.