The purpose is to segment the website's users according to factors such as demographics and geographical location, in order to enable media and marketing agencies to structure and understand their target groups to enable customised online advertising.1 yearHTTP_fbpFacebookUsed by Facebook to deliver a series of advertisement products such as real time bidding from third party advertisers.3 monthsHTTP_gcl_auGoogle Tag ManagerUsed by Google AdSense for experimenting with advertisement efficiency across websites using their services.