Below are some articles on how to create and manage hard links(aka directory junctions) in Windows NT/XP/2003 and also manipulate the underlying mechanism, reparse points. Directory Junctions can be used to make one folder look like another, not just be a shortcut. You can also mount a drive as a subfolder under another drive. These are called volumne mount points.
Aside from those two, reparse points are also used in Windows for Remote Storage Service (RSS) and Remote Installation Services (RIS).

I'll repost this info on tech discussions.

http://support.microsoft.com/kb/262797/
http://support.microsoft.com/kb/205524/EN-US/
http://www.sysinternals.com/Utilities/Junction.html

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