Writing: Notational Velocity

A programm that can be used to take notes and makes it easy to search inside said notes is Notational Velocity.
The program shines espeially when taking notes for a book or project, means the notes share a common theme. The Notational Velocity Website contains a more thorough description of the program.
As a side-note: the program is Mac only and is a deviation of my mantra to only use software for writing that is available on all platforms I usually use (OS X, Linux, *BSD, Solaris).
BTW: If you are a Mac user, aren't you fed up with the fact that the description of many programs does not contain a hint (in the first two pages of their respective website, that is) that the software is running on something that should be wall-mounted in the first place? Just a thought...