Documents4Me by Stratusi includes the ability to add both manual and automated notes to documents within the system. Notes are timestamped and indicate what user created the note. Automated notes can be created based on a workflow activity like accepting or rejecting an invoice. Notes can also be appended into the document itself as either a header page or footer page.
Documents4Me permissions allow control over who can see notes, add notes, or delete notes. Admins have the ability to assign various roles and permissions to users.