A cookie is a file on your computer that can be placed by a website when you visit that site. The function of a cookie is so a website can differentiate between users. You will find cookies on websites where you need to log in, cookies make sure you stay logged in.
Lifetime of cookies
Cookies have a lifetime. Some cookies are removed when you close your browser. Others can stay on your PC for years. You can also choose to remove them every time.
You can’t see cookies yourself. And you can’t see what they are used for. Cookies are text files with unreadable content. The real data that belongs to a cookie is saved in the database of the website that placed them.
The ability for websites to differentiate and follow users is relevant to most sites. By following users and their behaviour, advertisement networks can serve personalized ads to those users. Take for example a webstore showing you “relevant products”. This is all made possible by cookies. Companies use this on a mass scale.
Tracking cookies are cookies that are placed on your computer by third parties to track what sites you used and how you use them. This is often used by advertisers to profile your behaviour. The benefit of these cookies are when you visit multiple sites serving these cookies from the same advertising network. The advertiser network can read the cookie and generate a profile based on your surfing behaviour.
Flash cookies are another type of cookie that gets used by Adobe Flash, a technology to give websites more interactivity. In the past, these cookies were nearly impossible to remove, but as of 2011, Adobe allowed browsers to remove them and now they are treated as normal cookies. Because of security, it’s important to keep Adobe Flash up-to-date.