If you hover a folder in Windows 7 you are getting something like the image below. Is there a way to change what this tooltip contains?
One method that requires no programming is to use Desktop.ini to create an infotip that displays custom information about the folder and controls some aspects of the folder's behavior.
This blog post outlines how to use them: http://msdn.microsoft.com/en-us/library/windows/desktop/cc144102.aspx
Desktop.ini file behaviors are generally inherited so the behavior can be applied to one or many folders, depending on where you place it.