At the DNUG conference we showed a new composite application running in the Notes 8 build-du-jour. While I don't speak German, and maybe you don't either, there is a nice picture from the demo that was built there. It connects our new contacts application with a discussion forum. And a new cloud tag app was built in Eclipse that reads the categories from the Notes forum. The picture in the article shows the Composite Application Editor, which is how you can set up the connections among the different components in your app.
Heise Online - IBM zeigt Composite Applications in Lotus Notes 8
Volker Weber on Composite Applications