Google Personalization

 

The short story is this. By watching what you click on in search results, Google can learn that you favor particular sites. For example, if you often search and click on links from Amazon that appear in Google’s results, over time, Google learns that you really like Amazon. In reaction, it gives Amazon a ranking boost. That means you start seeing more Amazon listings, perhaps for searches where Amazon wasn’t showing up before.

The results are custom tailored for each individual. For example, let’s say someone else prefers Barnes & Nobles. Over time, Google learns that person likes Barnes & Noble. They begin to see even more Barnes & Nobles listings, rather than Amazon ones.

Of course, people will be clicking on a variety of sites, in search results. So it’s not a case of having one favorite that that simply shows up for everything. Indeed, Google’s other ranking factors are also still considered. So that person who likes Amazon? If they’re looking for a plumber, Amazon probably isn’t close to being relevant, so the personalization boost doesn’t help. But in cases where Amazon might have been on the edge? Personalization may help tip into the first page of results. And personalization may tip a wide variety of sites into the top results, for a wide variety of queries.

To personalize results, Google has to record what you’re doing — and that rings privacy alarm bells. Can people see what you’ve looked for? How long is the material kept? Can you just turn it off?

You can turn it off. A history is kept for 180 days. You can delete that history at any time, but even if you don’t, it can’t actually be viewed.

In particular, we now have two “flavors” of personalized search, or “Web History” as is the official Google name for it. There’s Signed-Out Web History and Signed-In Web History.

In Signed-Out Web History, Google knows that it has seen someone using a particular browser before. Behind the scenes, it has tracked all the searches that have been done by that browser. It also logs all the things people have clicked on from Google’s search results, when using that browser. There’s no way to see this information, but it is used to customize the results that are shown. It only remembers things for 180 days. Information older than that is forgotten. Google doesn’t know your name. If you use a different browser, Google doesn’t know your past history. In fact, you can’t even see your past history.

 

In Signed-In Web History, Google knows that a particular Google user is using Google. Behind the scenes, it has kept a record of all the things that person has done when signed-in, regardless of what computer or browser they’ve used. If they’re using the Google Toolbar with the page tracking feature enabled, then it has also kept a record of all the pages they’ve viewed over time. This information can be viewed by the user at any time, and the user can selectively delete info. They can also delete everything, if they want.

 

If they don’t, then Google forgets nothing.