A few weeks ago I was reading through the Wikipedia entry on NTFS, and noticed that it was possible to use Symbolic Links amongst a number of other features that aren't readily apparent in Windows Explorer.
What other useful features exist that may not be documented on Wikipedia, and how does one get access to these features? Is there a 3rd party program, registry settings, hidden configuration windows, cli, etc. used to manipulate/create/use these features?
Update: Turning this into a community wiki.