- Users want to be able to make sure they are the only ones who can use
their email address (no spoofing)
Probably unrealistic,
Who said users were realistic? We're talking about what users want,
not what they can get.
bounces are a whole area to be deciphered. Return receipts are a
potential privacy concern --- there should be a mechanism to request
one, but the receiver should have final say on whether it's returned or
not.
Again, we're talking about what users want. Senders requesting a
receipt notification want a guarantee that they'll get a notification
if the recipient receives the message. Recipients want to be able to
read the message without generating a notification, or at least,
to be able to refuse to read the message.
Yes, this is contradictory. That's how users are.
Keith
p.s. If you use the term "return receipt" you need to define what
you mean. There's not a single obvious meaning of the term, and the
differences between the meanings are significant. Terms like
"delivery notification" "receipt notification" and "read notification"
are more precise, but even then there can be a lot of wiggle room.