An .htaccess file is a text file that features directives that tell a server how to behave in particular occasions. It needs to be put in the folder in which these directives should be carried out. Loads of script-driven apps use this kind of a file to operate efficiently - WordPress and Joomla™, in particular. You can use such a file with customized content as well and do a lot of things - block an IP address, an entire network or certain sites from accessing your site, set custom made error pages that will appear instead of the server-generated ones in case a visitor encounters some error on the website, redirect a domain or a subdomain to a different web address, set up a password-protected area plus much more. With an .htaccess file, you'll have much better control over your presence online.