What are cookies on the internet?
Cookies on websites are small text sequences of information that are stored directly in the browser. A cookie has a specific name and a specific value, both made up of arbitrary strings.
They are mainly used to store useful things like your login or which items you have in your shopping cart.
In these two cases, they remember the state on a website and they belong to the group of functional cookies.
Why is this necessary at all?
The nature of the internet is such that a certain state cannot be remembered.
Imagine your online banking without cookies. After each new page view you would make there, you would have to log in again.
So on the one hand, cookies are useful, but they can also be abused.
What do cookies have to do with data protection?
Data collectors can set cookies and use their names and values to read pairs that reside on your browser to accurately read your browsing behaviour. When you go to a website where these cookies are then read out again. Many large advertising companies use website cookies to deliver personalised advertising.