Every server automatically compiles a log of every hit for every user session. The log is simply a text file in a structured format that can be interpreted by traffic analysis software to reveal patterns and details of activity on the Web site. Server logs record the Internet Protocol (IP) address of the user during each session, but no other aspect of the user's identity is known. Dynamic IP addressing, used by all dialup service providers, make it impossible to track a specific user from one session to the next.