When a user connects to the site, the server accepts the connection.
The server sends this value in the form of a cookie to the user's browser.
Until the connection is abandoned or times out, the server will use that value to mark the user's requests so it can return the requested files to the right place.
When a new user connects to the server, the server again consults an internal value, increments it by one, and assigns that value to the new user's connection
