If you’re anything like me, you probably have a personal log-in for multiple websites, including online retail stores, a personal bank account, maybe a news source and, of course, social sites. If you are an observant Web searcher, you may have noticed that, while logged in, these sites display advertising or recommendations based on your recent purchases or information supplied in your profiles.

For example, if you’re a Netflix subscriber, the site will make future rental recommendations based on the previous movies you rented. The same tactics are used on social sites such as Facebook, which often shows ads it feels are relevant to your interests. Even YouTube logs a record of the videos you view, and it will remember these during your next visit to make suggestions.

This tactic is commonly known as behavioral targeting and is typically used by sites that require a membership or log-in. It’s no secret that Google uses behavioral targeting to track search histories of members who sign in; however, as of Friday, Google is now tracking the behaviors of searchers who sign out, serving search results based on these past behaviors.

With this change, there are now two types of Web Histories, and each of these record different things:

• Signed-Out Google Web History records usage from someone using a certain browser (new).
• Signed-In Google Web History records history from someone who is logged in to Google.

A noteworthy feature is that Google set up this new personalized search system as an opt out rather than an opt in. This means that all Google users (signed in or not) are automatically affected by the change if they don’t intentionally choose to opt out.

As usual, Google is the first search engine to implement targeting capabilities of this level and, as the Web continues to become more sophisticated, I can’t help but wonder if this targeting will become widely used across other search engines. Next time you use Google, make sure to take a closer look at the search results for new trends. I know I will.