The Help->About dialog in GUI applications has historically been the place for some very "interesting" (and often funny) functionality and easter eggs.
How would you define the purpose of the About dialog? What function does it serve in an application, and who is the target audience?
What's the best use (or abuse) of an About dialog that you've seen?
In my experience its for the product version number, to list the loaded modules, copyright information and credits for the developers.
The best (serious) use I have seen has been Visual Studio that can have a number of loaded packages and add ons.
I would think the target audience is legal people, installer/administrators, developers and other technical people. I can't imagine many non technical people bothering to view it.
Wikipedia says the origins of the About box are
"The concept of the about box originated with the first Macintosh operating system, where About [program name] was typically the first item in the Apple menu"
In addition to the above, it is often used as an area to provide contact details to the vendor and their technical support. I also tend to put a certain amount of system information in here for the aid of the tech support people when they are contacted.
It helps to ensure that every windows desktop app has at least two top level menus (one just looks silly) - even the worst GUI developer wouldn't shove the About menu option on the File menu. Would they?