Downloading GhostNote 2.2 for Mac from the developer's website was possible when we last checked. We cannot confirm if there is a free download of this app available. This software for Mac OS X was originally developed by Thomas Petersen. Please check the Mac app with an antivirus before launch as it is downloaded from the developer's website, and we cannot ensure that it is safe. The application is included in Productivity Tools.
From the developer:
GhostNote is an application that adds contextual notes to almost anything on your Mac. With this program, you can add notes and to-dos to folders, applications, open documents, even to websites. You may think about this utility as post-it notes for your OS.
You may want to check out more software for Mac, such as Currency Assistant, SOHO Business Cards or Mémoires, which might be related to GhostNote.