It would be so great if QB could add the feature to see who specifically viewed an invoice.  I know that I can pull a pdf of the invoice but I like to cc myself on the email when I send the invoice from QB initially.  It really defeats the purpose of even having the feature to show that it has been viewed if I cc myself and just by opening the email (you don't even have to click on the "Review and Pay Invoice" button in the email) it shows "Viewed" as status.