My previous job was in IT. So I can try and explain cookies in terms anyone can understand.
A cookie is a way for a browser to remember something. There are essentially 3 types. Temporary, time limited and permanent. Temp last just while the browser is open and are just in RAM, so no file. time limited have an expiry date but do write a file and permanent last forever.
Only the server that issues the cookie and read it. Nobody else. (well you can read your own but google.com can't read a microsoft.com cookie).
So this all sounds ok, but many sites use the same plug ins on their web site, each coming from their own server and each have their own cookies.
A "good" use of a cookie is where a web site remembers who you are, so you don't have to keep logging on.
"Bad" cookies, we can call them that for now, can be used for targeted advertising. Lets use google as an example. If you search on google for something, lets say a hat, google can write to the google.com cookie that you might be interested in a hat. Then you visit another site, say an online store, that have google provided adverts, well that advert can read the your google.com cookie and decide to show you hat adverts. Now if that store pays google to only show things that they sell, suddenly you see them offering you their hats and you might wonder how did that do that.
Is this really bad, well that's up to you.
EU regulated cookies as someone discovered that the browser is writing a cookie (a text file) on your computer (in your cookie storage area, nowhere else) without having to be asked, so potentially without your knowledge or permission. So they put in law that you have to ask permission before you can write a cookie.
Hope this helps. Cookies are actually pretty simple but can be used in cunning ways.
Back when I first was introduced to the internet, I was told never to type anything in you are not prepared to stand up and say to anyone and everyone.
On the internet nothing is private.
Hope this helps
