Cookies

Each unique browser that visits a page on your site is provided with a unique ID via the __utma cookie. Thus, if a person interacted with your website using both Firefox and Internet Explorer, the Analytics reports in most cases will track this activity under two unique visitors. Similarly if the same browser were used by two different visitors, but with a separate computer account for each, the activity would be recorded under two unique visitor IDs. On the other hand, if the browser happens to be used by two different people sharing the same computer account, in most of the cases one unique ID is recorded, even though two unique individuals accessed the site.

The Google Analytics tracking for ga.js uses two cookies to establish a session. If either of these two cookies are absent, further activity by the user initiates the start of a new session. See the Session article in the Help Center for a detailed definition and a list of scenarios that end a session. You can customize the length of the default session time using the _setSessionCookieTimeout() method.

When visitors reach your site via a search engine result, a direct link, or an ad that links to your page, Google Analytics stores the type of referral information in a cookie. The parameters in the cookie value string are parsed and sent in the GIF Request (in the utmcc variable). The expiration date for the cookie is set as 6 months into the future. This cookie gets updated with each subsequent page view to your site; thus it is used to determine visitor navigation within your site.