General talk about software patterns

[Al Boldi <a1426z AT gawab.com>]

Messaging Design Pattern 
<dsheppard2k AT yahoo.com>
 wrote:
> I'm glad that the real world analogies served their purpose. At the very
> least they encouraged the reader to think in terms of a realistic software
> model (based on messaging) that mimics the world around us. The main goal
> of this discussion is the to clarify or expand on specific points not
> covered by the paper.
>
> In terms of reusability, there are several areas where  the messaging
> design pattern  (MDP) provides improvements:

Can the MDP be used to replace the Observer Design Pattern?

If so, would the system be easier or harder to implement in the long-run?

What about performance and resource usage?

When is the MDP applicable, and when is it not applicable?


Thanks!

--
Al