A "cookie" is a small text file containing a string of alphanumeric characters. There are two types of cookies: a persistent cookie and a session cookie. A persistent cookie gets entered by your Web browser into the cookie folder on your computer's hard drive. A persistent cookie remains in that cookie folder, which is maintained and governed by your Web browser, after you close your browser program. A session cookie is temporary and disappears after you close your browser. DoubleClick's ad serving and paid search listing ("DoubleClick Search") products utilize the same cookie: the DoubleClick cookie. The DoubleClick cookie is a persistent cookie and consists of the name of the domain that set the cookie ("ad.doubleclick.net"), the lifetime of the cookie, and a "value." DoubleClick's technology generates a unique series of characters for the "value" portion of the cookie.
Web beacons are small strings of HTML code that are placed in a Web page. They are sometimes called "clear GIFs" (Graphics Interchange Format) or "pixel tags." Web beacons are most often used in conjunction with cookies. DoubleClick uses Web beacons in connection with its products and services, including ad serving and paid search listings ("DoubleClick Search"). Because a Web beacon is only 1 pixel high by 1 pixel wide, it appears invisible on your computer screen. If Web beacons were made larger (e.g., 100 pixels high by 100 pixels wide), it would take much longer for your Web page to load and would clutter up the page that you have requested.
The DoubleClick cookie helps marketers learn how well their Internet advertising campaigns or paid search listings perform. Many marketers and Internet websites use DoubleClick's technology to deliver and serve their advertisements or manage their paid search listings. DoubleClick's products set or recognize a unique, persistent cookie when an ad is displayed or a paid listing is selected. The information that the DoubleClick cookie helps to give marketers includes the number of unique users their advertisements were displayed to, how many users clicked on their Internet ads or paid listings, and which ads or paid listings they clicked on.
When you visit any website or search engine on which DoubleClick's technology is used, our servers will check to see if you already have a DoubleClick cookie. If the servers do not receive a DoubleClick cookie, the servers will try to set a cookie in response to your browser's "request" to view that Web page. If you do not want a DoubleClick cookie with a unique value, you can obtain a DoubleClick "opt out" cookie. Alternatively, you can adjust your Internet browser's settings for handling cookies. This is explained in the next question.
To eliminate cookies you may have currently accepted, and to deny or limit cookies in the future, please follow one of these procedures:
Important: If you delete your opt-out cookie, you will need to opt-out again.
If your browser blocks all or third-party cookies, you will block the setting of opt-out cookies.
If you are using Internet Explorer 6.0, go to the Tools menu, then to Internet Options, then to the Privacy tab.
This version of Internet Explorer is the first to use P3P to distinguish between types of cookies.
P3P uses standardized privacy statements made by the cookie issuer to manage your acceptance of cookies.
Under the "Privacy" tab, click on the "Advanced" button.
Select "Override automatic cookie handling" and choose whether you want to accept, block or be prompted for "First-party" and "Third-party Cookies."
If you want to block all cookies coming from DoubleClick's doubleclick.net domain,
go to the "Web Sites" section under the "Privacy" tab and click the "Edit" button.
In the "Address of Web site" field, enter "doubleclick.net," select "Block," click OK (menu will disappear);
click OK again and you will be back to the browser.
If you are using Netscape 6.0+, go to "Edit" in the menu bar, click on "Preferences," click on "Advanced," and select the "Cookies" field.
Now check either the box that says, "Warn me before accepting a cookie" or "Disable cookies." Click on "OK."
Now go to your "Start" button, click on "Find," click on "Files and Folders," type "cookies.txt" into the search box that appears, and click "Find Now."
When the search results appear, drag all files listed, into the "Recycle Bin." Now shut down and restart your Netscape.
Depending on your earlier choice you will either be prompted by new cookie sets or no cookies will be set or received.
If you are using Mozilla or Safari, please go to their websites to find out how to disable cookies in those programs.