You can use desktop.ini to create an infotip that displays information about the folder and controls some aspects of the folder's behavior.
If you set InfoTip to an informational text string, it is displayed as an infotip when the cursor hovers over the folder.
Look here for more information: msdn.microsoft.com/en-us/library ... 85%29.aspx
And look here for a solution: [InfoTip does not work in DOpus)