The Facebook API is very powerful and it allows you to create your own Facebook applications, which you, your friends or everyone else can then consume. You can use the Facebook applications you build on profile pages, canvas pages, and so on. You can even make money by developing practical applications.
Sachin Khosla's PHPBuilder.com tutorial "PHP Development on the Facebook Platform: Building Your First App" demonstrates how to create your own Facebook application, using PHP as the language (Ruby on Rails, Python, and others are supported) and Facebook's Status Updater application as the example. All you need to do to get started is:
- Add Facebook Developer Application to your Facebook account.
- Add your first Facebook application.
Sachin walks you through all the details.