PHP, which is an acronym for PHP: Hypertext Preprocessor, is one of the most widely used dynamic programming languages out there. Any site or Internet application built using PHP will run on a given server as long as a PHP module is activated, which makes the language really universal and it is not that unusual that there are actually a couple of million web servers that support it and hundreds of millions of PHP-powered websites hosted on them. PHP is preferred over HTML thanks to the fact that it allows you to create a dynamic website with a multitude of features. A PHP-based social network, for example, will serve unique web content to each user regardless of the fact that the URL will remain unchanged. On the other hand, HTML websites are static and the content on the pages can be modified only manually. Like any other software program, PHP has several versions and the version that was used while setting up a given website must be activated on the web server so that the site can run flawlessly.