The Facebook Platform was launched on May 24, 2007. The purpose of the Facebook Platform is to act as a framework for web developers to create applications that interact with Facebook. The types of applications vary, from news feeds to games such as Chess.
While the Facebook Platform has received some critism from the coding community (and from the Facebook users community), it remains as the best way to customize a Facebook profile. The Facebook Platform has become so popular that some colleges, such as Stanford, are now offering computer courses that teach the trade of creating applications for the popular social networking giant.
Application developers are allowed to customize the appearance of their applications by using a modified version of HTML called Facebook Markup Language (FBML). This language is what developers must use if they want their Facebook Platform applications to work properly on the Facebook server.
Creating a Facebook Platform application requires knowlege of FBML, PHP, and in some instances mySQL. If you are interested in creating a Facebook Platform application, you should have a programming background. Another useful programming language for the creation of Platform applications is Ajax.
With all of that being said, the Facebook Platform allows developers to cleanly integrate custom applications into the Facebook system.