The Experience Services contains the Composite Application Framework (Mosaic). The framework has both a server component and a Flex component. Adding the ADEP tooling plugins will, among other things, provide Mosaic capabilities to Flash Builder.
Mosaic builds on the OSGi-inspired Gravity framework. It provides a Flex sdk and tools for creating Mosaic applications, functionality within Flash Builder to create catalogs and deploy applications to a server, and the Mosaic server to present the applications over the Internet.
Content, both Flash-based and HTML, can be brought to together into an application as individual tiles. The tiles can be existing content recompiled with Mosaic tags or it can be new content. The tiles do not all have to have been compiled with the same Flex SDK. The tiles can be developed independently of each other by separate team or at different times. And the tiles can be reused in other applications.