If there is no action you need to take, you might want to keep it temporarily or else place it into your long-term filing cabinet.
1. Project Files: If it's an ongoing activity and you want to track the progress, have a temporary folder on your desktop. You can delete the folder at the end of the project.
2. Reference Files: You want to retain the note for future reference, so you might print that and put it into your paper filing system, or save it in a related folder within 'My Documents'.