Multi-platform mobile application development allows creating apps that can run across different devices using a single code base. Titanium, an open source framework from Appcelerator, uses JavaScript to build native mobile apps that can run on iOS, Android, and BlackBerry. It provides APIs to access native device capabilities while maintaining a consistent programming model. The document demonstrates a proof of concept multi-sport news app built with Titanium that pulls data from cloud services, stores cached data locally, and presents a native user experience across platforms.