An error log is a listing of the error messages and warnings that displayed for one reason or another while your visitors were surfing around your site. This sort of a log contains raw information about the way the server has addressed requests in various situations. An error message could appear if, for example, a link leads to a webpage or a file that is not on the web server, if the code on a given page cannot be processed, if anyone is trying to access the website or its back office using an IP address that is blocked by an .htaccess rule and so forth. The data inside the error log features the IP address of the site visitor, what error message displayed and the cause for the server to show it, the full path to the file which generated the error and the specific time of the event. Having this data will help you figure out if any part of your website has an issue, which you can then take care of. Consequently, your site visitors will have a better experience and you may optimize the site for best performance.