An .htaccess file is a text file that contains directives which tell a server how to operate in certain situations. It should be put in the folder in which these directives should be performed. Many script-driven apps use this kind of a file to operate properly - WordPress and Joomla, for example. You can use this sort of a file with customized content as well and do quite a lot of things - block an IP address, a whole network or specific Internet sites from accessing your site, set custom made error pages that will show up instead of the server-generated ones if a visitor encounters some error on the website, direct a domain or a subdomain to another web address, create a password-protected area plus more. With an .htaccess file, you'll have significantly better control over your online presence.