Answers:
In a nutshell, it's a set of standards or interfaces to the an assortment of components on an operating system that can be used by direction tools or administrator to receive information and rub down said system. It allows both local and remote resources of administrative access. It's commonly used in scripting, and I believe by Microsoft's own headship software such as Microsoft Operations Manager (MOM).
See the Wikipedia article for more in-depth explanations.