The cookie was created in 1994 by an employee of Netscape Communications, the same company that made the browser. He was creating an online shop, and he didn’t want to store the contents of the shopping cart on the server. Instead, he wanted a way to save it on the computers of the visitors, right until they made their purchase. The reason for this is simple: if the server doesn’t have to keep track of everyone’s shopping cart, it has less work and can save money. In 1994 the Netscape browser implemented cookies and the next year Internet Explorer followed suit. However two years later – in 1996 – the first concerns were raised when it was discovered that cookies could potentially invade our privacy. That would turn out to be very true, but we’re getting ahead of ourselves here.
Let’s take a look at how cookies work. Let’s imagine we have a website that requires people to log in to see the contents of the site. When you log in, your browser sends your username and password to the server, who verifies them and – if everything checks out – sends you the requested content. However, there is a small caveat. The HTTP protocol – which is what we use to browse the internet – is stateless. That means that when you make another request to that same server, it has forgotten who you are and will ask you to log in again. Can you imagine how time-consuming it would be to browse around a site like Facebook and having to log in again every time you click on something? So cookies to the rescue! You still log in to the website, and the server still validates your credentials. If everything checks out, however, the server not only responds with the content but also sends a cookie to your browser. The cookie is then stored on your computer and submitted to the server with every request you make to that website. The cookie contains a unique identifier that allows the server to “remember” who you are and keep you logged in. As you can see, cookies are very useful, and they make our lives a lot easier. But it doesn’t stop there! Besides keeping you logged in, cookies can also be used to store your settings. Let’s say you change the number of results your favorite search engine should return. Chances are high that they save this preference in a cookie and not on their servers.