How can I find out if an e-mail I sent through Yahoo mail has been opened by its reciever who has hotmail?

you pick up the phone and call to ask if they got it
How can I find out if an e-mail I sent through Yahoo mail has been opened by its reciever who has hotmail?
Dude, you can't.
Reply:You would have had to active the "return receipt" function when you originally drafted/sent the email.
Reply:Ask the receiver, there is no electronic way of finding that out