An access log contains a record of all the files which have been requested by the visitors while surfing around your site. The list is thorough, so in case you have a web page with 2 embedded images, for instance, all of the three files shall be in the log, not only the page. An access log normally includes the date, the Operating System, the Internet browser and the IP address for each file in human-readable form, so you can get a good idea about the most well liked files on your site. The log, which is also commonly referred to as "raw data", is an addition to the web statistics you usually get with a hosting account, not a replacement. A good example why you may need this kind of a log is if you intend to use some software on your personal computer to prepare a report about the website’s general performance, but you do not want to use the typical graphs and tables that come with the server-generated website statistics.