An error log is a listing of the error messages and warnings which appeared for one reason or another while your visitors were looking through your website. This kind of a log provides raw information on the way the web server has addressed requests a number of situations. An error message might appear if, for example, a link leads to a website or a file that isn't on the hosting server, if the code on a given page can't be processed, if somebody is trying to access the website or its back office through an IP address that is blocked by an .htaccess rule and so on. The info inside the error log features the IP of the visitor, what error message came out and the basis for the server to show it, the whole path to the file which generated the error and the specific time of the event. Having this info will permit you to figure out if any part of your site has a problem, which you may then fix. As a result, your site visitors will have a better experience and you'll supercharge the website for maximum performance.