Some mails could greatly benefit from notes being added to them as they are processed.
A simple button activated pop-up like the ones in Sticky Notes would be fine, especially if it had a timestamp for each entry.
That way we could add comments to mails without editing the mail itself, and keep track of when they were added.
An indicator in the preview, showing that the mail has comments would be splendid.
- And the option to view and search comments would make it absolutely stunning.