Application compatibility

"When addressing application compatibility issues in preparation for a deployment of Windows® 7, among the most flexible and powerful tools available are application compatibility fixes, or shims. However, most organizations do not leverage shims to the extent that they could, either because they don't understand the underlying technology or because they do not have a process in place to manage shims over the lifetime of the applications they manage."
-Microsoft Technet

Application compatibility features

Chris Jackson from Microsoft is known as the "AppCompat Guy", and most useful information is from Chris. Links include: