The document discusses strategies for sharing code between Windows 8 and Windows Phone 8 applications. It recommends using common structures like Model-View-ViewModel, copying and linking code between projects, and using #if conditional blocks. Portable Class Libraries allow sharing a single code base across multiple platforms. The document emphasizes focusing on an experience tailored for each device's form factor while maximizing code reuse through these techniques. It provides examples of adapting UI elements like grids and lists between Windows and Windows Phone.