Ads Preferences

Interest-based advertising: How it works

Many websites, such as news sites and blogs, join the Google Display Network, which enables Google to show ads on their sites. It's our goal to make these ads as relevant as possible for you. While we often show you ads based on the content of the page you are viewing, we also show some ads that you might find useful based on the types of websites you like to visit.

The following example explains this technology step by step:

Meet Mary

Mary's favorite hobby is gardening. With Google's interest-based advertising technology, Mary will see more relevant gardening ads because she visits many gardening websites. Here's how that works:

1. When Mary visits websites and watches videos in the Google Display Network or other partner sites, Google stores a number in her browser (using a "cookie") to remember her visits. That number could look like this: 114411.
2. Because many of the websites that Mary visits are related to gardening, Google puts her number (114411) in the "gardening enthusiast" interest category. Similarly, if those sites have a majority of female visitors (based on aggregated survey data on site visitation), her number (114411) may be added to the 'female' inferred demographic category.
3. As a result, Google may show Mary more ads that are relevant to gardening enthusiasts and women as she browses websites that are part of the Google Display Network or partner sites.

No personal information

Throughout this process, Google does not know Mary's name or any other personal information about her. Google simply recognizes the number stored in Mary's browser, and shows ads related to the interest and demographic categories associated with her cookie.

Google will not show ads based on sensitive information or interest categories, such as those based on race, religion, sexual orientation, health, or sensitive financial categories.

Editing interests with the Ads Preferences Manager

Google lets Mary edit the categories associated with her browser's number. In addition to gardening, Mary likes to play golf, so she adds this interest using Google's Ads Preferences Manager. Now she will also see more ads about golf. Mary can also edit or add to the inferred demographics that Google has associated with her cookie.

Using a different computer or clearing the browser's cookies

Anytime Mary uses a different browser or computer, her number won't carry over because it is specific to the browser she used before. When Mary clears her browser's cookies, the number is deleted and Google no longer associates Mary's browser with those interests or inferred demographics.

Opting out

If you prefer not to receive this type of interest-based advertising, you can always opt out by clicking the "Opt out" button on the homepage of the Ads Preferences Manager. After you opt out, Google will not associate interests or demographics with your cookie, and you will not receive interest-based ads. You will see the same number of ads as before, but they may not be as relevant.

For more information, check the Frequently Asked Questions and visit the Advertising and Privacy page of our Privacy Center.