Kat - It's not surprise that it can be done. The SPAMMERS have known about this for a long time, although it appears in actual use they seldom bother to track their stuff with covert receipts. If you don't click something, they've got too many other really stupid people to chase who do click.

My question is why anyone would want or need a receipt without letting the recipient know you've asked for it. Most email programs allow you to check a "receipt" box that will send an email back to you when the mail is opened - but it does tell the recipient that it's doing it.

If I send something to a friend, and feel the need for a receipt, friend is entitled to know I'm confirming the mail.

If I send something to a "less friendly" and want a receipt, it's usually to impress them that I'm keeping track - and for sure I want them to know it.

John