input: [Category of use] Session State [Example] 
output: Websites often collect information about how users interact with a website. This may include the pages users visit most often, and whether users get error messages from certain pages. We use these so-called ‘session state cookies’ to help us improve our services, in order to improve our users’ browsing experience. Blocking or deleting these cookies will not render the website unusable. These cookies may also be used to anonymously measure the effectiveness of PPC (pay per click) and affiliate advertising. For example, we use a cookie called ‘recently_watched_video_id_list’ so that YouTube can record the videos most recently watched by a particular browser.