An access log contains a record of all the files which have been requested by the visitors while surfing around your website. The list is thorough, so when you have a page with 2 embedded images, for example, all of the three files shall be in the log, not only the page. An access log typically contains the date, the OS, the browser and the IP address for every file in human-readable form, so you can get a good idea about the most well liked files on your website. The log, that's also frequently called "raw data", is an addition to the web statistics you typically get with a hosting account, not a replacement. An example why you could need this type of a log is if you want to use some software on your computer to prepare a report about the website’s overall performance, but you do not want to use the conventional graphs and tables that come with the server-generated site statistics.