A file which contains important information about the accesses to Web pages made by users. For example, every time a browser requests a page, an entry is automatically made in this file by a Web server, containing information such as the time at which the access was made, the address of the computer on which the browser was running, and the transfer time of the page. Such information is exceptionally useful. For example, it allows technical staff to judge whether certain pages should be kept in a fast storage medium in order to optimize them.