What are cookies?
The simple guide to computer 'cookies'
First things first
In contrast to popular belief, cookies are not programs they are text files that are downloaded onto your computer, your computer will automatically check for any relevant cookie files when it goes onto a website, and it if it finds one, it will send information back to the website.
They store useful data to make browsing easier in the future, such as privacy settings, and how long you spend on a site, and what things you use the most on the site.