The document provides information on various features available for building applications on Facebook's platform, including:
1. APIs and tools like the Facebook API, FBML, and FQL that allow integrating applications and accessing user data.
2. Widgets and tags like Fb:comments, Fb:live-stream that allow embedding social features from Facebook into applications.
3. Frameworks for building applications using either FBML for tighter Facebook integration or iFrames for easier debugging and integration of third-party code.