[DR300] Simplicity and layering

I think I'd like to see some discussion as to what an 'application' is in
this context. One could argue that certain 'facilities' ( e.g.
transactions ) are in fact applications in this context, that is they are
not part of XP per se, but run on top of XP. I don't want people getting the
idea that XP does everything up to the business ( or other ) application
boundary. Maybe a reference to use cases would be useful here...

Gudge