A fortune cookie is a biscuit that contains a little message of good luck or a saying. On the internet, a cookie makes the user’s life easier. It is designed to recognise you so as to facilitate your web navigation. Once it has identified you, the cookie follows you when you visit a website, memorises your preferences such as language, your ongoing searches, or your most recent visits to an online store. But, it can also play tricks on you. It is a witness to what you do online: each time you connect to a website, or download an application, you leave a trace on the web, which is why the cookie is sometimes referred to as a spy. It allows data about your internet behaviour, the sites you visit, and so on, to be gathered and stored.