Google Analytics employs cookies to define user sessions, which allows for the collection of data about how visitors are using the websites. Google Analytics uses only first-party cookies for data analysis. This means that the cookies are linked to a specific website domain, and Google Analytics will only use that cookie data for statistical analysis related to your browsing behavior on that specific website. According to Google, the data collected cannot be altered or retrieved by services from other domains.
If you choose, you can opt out by turning off cookies in the preferences settings in your web browser. For more information on Google Analytics, please visit Google Analytics
Google Analytics Terms of Service http://www.google.com/analytics/tos.html
Google Analytics Cookie Usage on Websites https://developers.google.com/analytics/devguides/collection/gajs/cookie-usage