Anatomy of an Application

• An app can appear on many different pages.

• Application Directory
• About Page
• Left Nav
• Facebook Canvas Pages
  • Home
  • User Dashboard
• Profile
  • Profile Box
  • Profile Action Links
• Privacy Settings
• News Feed
• Alerts
• Message Attachments
• Requests
• Interacting with Users

You set your callback (URL) for each of these on the facebook website. They all require you to send back different markup.