Microsoft Knowledge Base Article 272203 contains the following summary:

The IntelliMirror management technologies are a set of powerful features built into Windows 2000 to increase reliability and reduce the overall cost of supporting users of Windows. IntelliMirror uses policy-based Change and Configuration Management to enable users' data, software, and settings to follow them throughout a distributed computing environment, whether they are online or offline.

The IntelliMirror features increase the availability of a user's data, personal computer settings, and computing environment by intelligently managing information, settings, and software. Based on policy definitions, IntelliMirror can deploy, recover, restore or replace a user's data, software, and personal settings in a Windows 2000-based environment.