PHP is an acronym for Hypertext Preprocessor and is an open source server-side programming language that is used for web development and can be easily embed with HTML. According to Wikipedia, PHP was used on over 240 million websites and 2.1 million web servers in January 2013.
This programming language has become so popular, that almost every hosting company includes it to their web servers and it can be used also on most operating systems as well. PHP can be used from creating a simple script to create complex applications such as forums or online shops, that process huge amount of data.
PHP is easy to learn
The very good this about PHP that it is very flexible, can be easily installed to any system and it is an easy to learn programming language. As mentioned above, it is mostly used to create web applications to create dynamic web-pages, but it is used for command line scripting and desktop graphical user interface applications as well.
Thanks to its flexibility, many software frameworks that provide building blocks and design structure such as CakePHP, Yii Framework, Zend Framework, has been relying on PHP. Popular content management system and website building tools such as WordPress, Joomla, Drupal and many others are built with PHP and most popular sites like Facebook or Digg are using this server-side scripting language in some parts of their website.