[aberkowitz]

I have never worked in a large enterprise, or a Fortune 500 company, but email receipts are a necessary evil. Certain industries rely on time sensitive work to be done base upon an email. If this doesn't happen, business is lost and contracts fall through.

While I strongly dislike Outlook, their opt-in read-receipts are the best implementation that I know of as far as privacy and ease-of-use are concerned.