Note: Cookies themselves contain no personally identifiable information. Depending on the publisher’s and the user’s settings, information associated with cookies used in advertising may be added to the user’s Google account.
Opting out of ads personalisation
If a user opts out of ads personalisation using Google’s Ads Settings, they will no longer receive personalised advertising from Google.
Google also use one or more cookies for advertising that it serves across the web. One of the main advertising cookies on non-Google sites is named ‘IDE‘ and is stored in browsers under the domain doubleclick.net. Another is stored in google.com and is called ANID. Google uses other cookies with names such as DSID, FLC, AID, TAID and exchange_uid. Other Google properties, such as YouTube, may also use these cookies to show you more relevant adverts.
Sometimes advertising cookies may be set on the domain of the site that you’re visiting. In the case of advertising Google serves across the web, cookies named ‘__gads’ or ‘__gac’ may be set on the domain of the site that you’re visiting. Unlike cookies that are set on Google’s own domains, these cookies can’t be read by Google when you’re on a site other than the one on which they were set. They serve purposes such as measuring interactions with the ads on that domain and preventing the same ads from being shown to you too many times.
Google also uses conversion cookies whose main purpose is to help advertisers determine how many times the people who click on their adverts end up purchasing their products. These cookies allow Google and the advertiser to determine that you clicked on the advert and later visited the advertiser site. Conversion cookies are not used by Google for personalised ad targeting and persist for a limited time only.
A cookie named ‘Conversion‘ is dedicated to this purpose. It’s generally set in the googleadservices.com domain or the google.com domain. Some of Google other cookies may be used to measure conversion events as well. For example, DoubleClick and Google Analytics cookies may also be used for this purpose.
When does AdSense send cookies to a browser?
AdSense sends a cookie to the user’s browser after any impression, click or other activity that results in a call to Google servers. If the browser accepts the cookie, the cookie is stored on the browser.
Most commonly, AdSense sends a cookie to the browser when a user visits a page that shows Google ads. Pages with Google ads include ad tags that instruct browsers to request ad content from Google servers. When the server delivers the ad content, it also sends a cookie. But a page doesn’t have to show Google ads for this to happen; it just needs to include Google ad tags, which might load a click tracker or impression pixel instead.
Notify users about cookies
Third-party and first-party cookies
Cookies are categorised as third-party or first-party depending on whether they’re associated with the domain of the site that a user visits. Third-party cookies are associated with a domain that’s different from the domain of the site that a user visits. The third-party cookies used by AdSense for advertising purposes may be associated with the doubleclick.net or country-specific Google domains such as google.com.
Note that this doesn’t change the name or content of the actual cookie. The difference between a third-party cookie and a first-party cookie is only a matter of which domain a browser is pointed towards. An identical cookie might be sent in either scenario.