James Governor pointed me at this excellent article which attempts to untangle the concepts of "Data marts" and "Data warehouses". I found it very helpful indeed.
I used to have very little time for debates over what we name things but such debates, run carefully, can be very useful at ensuring the participants completely understand the concepts. Jeff's piece is a perfect example of this in action. I started thinking about this when I blogged that I didn't think there was a difference between "Orchestration" and "Choreography" a few weeks back. I still don't think there's a real difference but there's a fascinating comment in there by Steve Ross-Talbot which has helped sharpen up how I describe some concepts.