An access log is a text file which contains a full report on all the files accessed by your website visitors. All of the files which were requested in one way or another shall be included, so if you have a PHP script app and a site visitor opens only the home page, for example, you might find a lot of files inside the log. This is because there are components on the home page which are embedded - parts of other Internet pages, pictures, and so on. All these files will be listed within the access log, allowing you to get a detailed picture of the way your site functions. The info is in plain text format, so the logs are sometimes called "raw data" too. An access log contains the name of every requested file, the path to it, the date it was accessed, and also the user’s IP address, browser and Operating System. More info, including the referrer website, is oftentimes included too. A log file could be processed by various desktop programs for statistical purposes as an addition to the web statistics generated by your server.