Server log files are inappropriate for gathering usability data. They are meant to provide server administrators with data about the behavior of the server, not the behavior of the user. The log file is a flat file containing technical information about requests for files on the server. Log file analysis tools merely assemble them in a conjecture-based format aimed at providing insight into user behavior. In the commentary below, I will explain why the nature of the web, the HTTP Protocol, the browser, and human behavior make it impossible to derive meaningful usability data from server logs.
