Imagine you had to log back in to a website every time you navigated to another page, or your favorite websites forgot all of your settings and you had to enter them again each time you visited?

Modern websites could not provide the usability and convenience we are used to without some way of remembering who you are and your previous activities on the website. HTTP is, by design, stateless-there is no persistence between one request and the next, and there is no way the server can tell whether successive requests come from the same person.

This lack of state is managed using sessions, which are a semi-permanent, two-way communication between your browser and the web server. When you visit a modern website, in the majority of cases, the web server will use an anonymous session to keep track of data relevant to your visit. The session is called anonymous because the web server can only record what you did, not who you are.

We have all experienced this when we have...