The Internet is a global data communications system that serves billions of users worldwide.  The Internet provides users access to a vast array of information resources and services, including those provided by the World Wide Web, intranet-based enterprises, and the like.  Typically, a user navigates from one page associated with a URL to another using a browser program.  The period of time that a user spends in this navigation is called a browsing session.  In addition, the order in which pages are visited during a browsing session can be called a browsing sequence. 
Internet users often revisit pages, both to obtain updated information and to re-visit information they have seen before.  It is conservatively estimated that users revisit nearly half of all pages they see.  Navigation aids that assist a user in re-finding previously visited site can be quite useful.