From Facebook Developer Wiki

A desktop application is an application that runs on a user's computer. This is different from an application that run inside a user's browser or within a platform such as the canvas pages available via the Facebook Platform. Desktop applications can be created using the Facebook Platform, and there are various differences between such an application and applications that exist within Facebook or Facebook Connect applications.

Configuring a Desktop Application

When configuring your desktop application in the Facebook Developer application, you must specify that it's a desktop application. On the Advanced tab in the application settings editor, select Desktop for Application Type.

Interacting with Facebook

Desktop applications can use Facebook API methods to interact with Facebook. FBML and FBJS are for the most part not available to desktop applications.

Authorizing a Desktop Application and Authenticating Users

Desktop applications use certain aspects of Facebook Connect for user authorization, authentication, and sessions. For more information, read Authorization and Authentication for Desktop Applications.

Related Topics

• Client Libraries
• Creating a Platform Application
• Platform Basics
• Platform Principles and Policies