Cookies are little teeny files that websites drop on your computer to identify you. As with edible cookies like chocolate chip and macaroons, you can love them or hate them. Computer cookies make life much more convenient for you. For instance, if you visit a website often, cookies store things like passwords, shopping cart contents, etc. But, they’re bad when they spy on you and give your information to creeps who use it to scam or spam you.
In general, cookies are harmless — except for what they do to your waistline.