An error log is a list of the error messages and warnings that showed up for one reason or another while your visitors were browsing your website. Such a log provides raw info on the way the hosting server has dealt with requests in various situations. An error message might appear if, for instance, a link leads to a page or a file that is not on the hosting server, if the code on a given page can't be processed, if anyone is trying to access the site or its back office using an IP address that's blocked by an .htaccess rule and so forth. The data inside the error log includes the IP address of the visitor, what error message displayed and the basis for the web server to display it, the whole path to the file which induced the error and the precise time of the event. Having this info will enable you to figure out if any part of your site has an issue, that you can then deal with. As a result, your website visitors will have a better experience and you will optimize the Internet site for maximum performance.