I've read through several articles and on-line help, but still can't
visualize what a UDM is. Here are my thoughts. Please bear with me if I sound
like a novice (I am).

Is it the analysis services database in SQL2005?  Is it something else?
Assuming it is analysis services database, I am confused when I see in
several books online docs where they compare UDM Vs. Traditional OLAP. What
is traditional OLAP then?

I read that UDM provides Heterogenous data sources, Proactive caching,  
advanced analytics like simultaneous executions etc. Weren't all these
present in AS 2000 to varying degrees?
Ex: AS 2000 provided connection to heterogenous data sources too. It allowed
HOLAP and let users store aggregations based on disk sapce constraints etc.
Isn't proactive caching just taking it to the next level  by providing higher
granularity in specifying what can be cached and what cannot?
Advanced analytics are something that is a an improvement in calculations.

Me and my collegues were discussing these, and one of things that was
mentioned is that UDM is an analysis services database with the Storage mode
switched to ROLAP. I now see only two choices for storage - MOLAP and ROLAP.
ROLAP was supported in AS 2000 as well.  I assume Proactive caching is the
replacement for HOLAP in AS 2005. Is UDM a regular analysis services database
with storage mode set to ROLAP?

These prompt me to ask - Is there a real distinction between an analysis
services database with cubes,  dimensions etc. and UDM, or are they one and
the same? Does it physically amount to something or is it a conceptual name
for for a group of some of the techniques? or is it probably a marketing hpye
or buzzword? (not that I see anything wrong with that)

What bothers me is that this UDM usage is ubiquitous in the books online
without any clear description of what it is and what it brings new comapred
to AS 2000 (I can't claim to ahve checked the entire BOL, so my statements
are restricted to my searches in BOL)? Are there any docs that can shed some
light on this?

Any thoughts and suggestions to help improve my understanding (and hopefully
others) is greatly appreciated.

Thanks