Opt out of interest-based advertising

In case you aren’t aware of this, every time you visit a site that has Google Adsense on it, and every time you visit a site that uses the DoubleClick ad management system, you have the potential for being tracked via a cookie that is injected to your computer. The cookie is known as the DoubleClick DART cookie, and, in fact, there is a very good chance that you are being tracked by one of these cookies.

Put another way, this cookie identies your computer with a unique value, and whenever the computer with that value (i.e. your computer) hits a site with the DoubleClick DART cookie, it’s tracked. That way when all of the data collected by your cookie is analyzed as a whole, a picture of your browsing habits emerges. Do you spend a lot of time on Amazon and B&N.com? Perhaps you’ll start seeing more ads for books. Do you spend most of your time on home improvement sites? You may see more ads for home-building and DIY companies.

What is the DoubleClick DART cookie?

The DoubleClick DART cookie is used by Google in the ads served on the websites of its partners, such as websites displaying AdSense ads or participating in Google certified ad networks. When users visit a partner’s website and either view or click on an ad, a cookie may be dropped on that end user’s browser. The data gathered from these cookies will be used to help better serve and manage ads on the publisher’s site(s) and across the web.

“Google uses cookies to improve your online experience, including the display of more relevant ads.”

When the cookie is set on your browser, it allows Google to gather information about your browser’s interaction with a given ad. This information gets recorded in a log that looks something like this:

time: 06/Aug/2008 12:01:32
ad_placement_id: 105
ad_id: 1003
userid: 0000000000000001
client_ip: 123.45.67.89
referral_url: "http://youtube.com/categories"

To Opt Out of Google’s DoubleClick Dart Cookie head to Google’s Privacy Center

Users can opt out of some, but not all, of these cookies in one location at the Network Advertising Initiative opt-out website at www.networkadvertising.org/managing/opt_out.asp.

Because publisher sites and laws across countries vary, we’re unable to suggest specific privacy policy language. However, you may wish to review resources such as the Network Advertising Initiative for guidance on drafting a privacy policy.