I have started working on ultimate ;) clarification of such terms like SOA, DDD, n-Tier, business entity, business layer, data access layer, persistence layer etc. and their place assignment in the enterprise applications' landscape... 

Look at first, early draft of graphic that I have called "Second Life of..."

And here a sample thought :) from my article:

The definition of a business entity is one o the most difficult things in the software architecture world. The problem that we have is this combination of words “business” and “entity”, the first depicts something very complicated and the second states for something simple – so we are trying to define something like “complicated-simplicity”…