Facebook is one of the largest social networking sites with over 200 million users around the globe. It provides a nice and complete platform to build social applications and tap into the Facebook users socialgraphs. 

Why build Facebook Social Apps ? 

There are several reasons to consider facebook platform as a development platform:

• Facebook provides the backbone social networking infrastructure such as profile management, friend management, private messaging and etc. This decreases the development time greatly since businesses don't have to worry about providing these features for their users
• With over 200 million Facebook users spread across thousands of networks, businesses can have a huge market share right in front of their door steps.
• Business can gauge the users' interactions using the Facebook usage statistics, providing them with an instant feedback. In addition users can leave constructive comments on the application review box.
• There are thousands of developers, entrepreneurs and businesses using the Facebook platforms daily. As a result companies can find a strong community to help them out when facing problems.

Integrate your site with Facebook.

Facebook Connect enables your site to integrate with the Facebook platform, enabling the users to 

• Seamlessly "connect" their Facebook account and information with your site
• Connect and find their friends who also use your site
• Share information and actions on your site with their friends on Facebook