Dynamic sets

The reason I'm discussing this often mentioned topic is the following. After many hours spent on the analysis how do dynamic sets behave in SSAS front-ends, I've been asked a perfectly reasonable question: Why do we have dynamic set and when should it be used? I believe this article explains the story behind dynamic sets and their purpose, as well as when and how they should be used. It also warns the reader that the problem is not about the implementation of dynamic sets in SSAS, but about something else. What? You'll see when you read it through.

INTRODUCING DYNAMIC SETS

SSAS 2005 and 2008 feature MDX script as a place to provide calculations. The reason is obvious - concentration of calculations on a server results in better query performance (precomputations, cache, etc.) and easier maintenance.