Google Now Keeps Track of Logged Out Users' Search History

Google wants to provide users with the most relevant results, it goes without saying and it's obvious why. Better results means satisfied users, but also that the ads served with the search are more likely to be of interest to them. But in order to provide better results, Google needs to know more about them, sometimes more than people would like it to know. And it's about to know even more, as Google has introduced Personalized Search to signed-out users as well.

“Today we're helping people get better search results by extending Personalized Search to signed-out users worldwide, and in more than forty languages. Now when you search using Google, we will be able to better provide you with the most relevant results possible,” Bryan Horling, software engineer, and Matthew Kulick, product manager, wrote.

“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,” they added.

So, how exactly does it work? When a user is signed in and has enabled Web History, Google will keep track of their previous searches and the results that were more relevant to them. This way, it can determine if the user has a preferred option between similar sites or for searches that may apply to more than one concept.

For signed-out users, there was no way of keeping track of their activity until now. Google will now store a record of the searches for the past 180 days for a particular browser in a cookie on the users’ machines. Every time a new search is made in that browser, Google will look up previous searches and preferences to provide a customized ranking of the results. When Google serves a custom results list, it will notify users with a link on top of the results section. They will also be able to disable Web History altogether, but the feature is enabled by default.