How can I know whether my email was read or not?

In hotmail, you add (confirm.to) after the email address, and you get confirmation once that message was read. It does not work for yahoo of course, is there something similar that could be done instead? 鈥?Their help site isn鈥檛 helpful.
How can I know whether my email was read or not?
Give them a call and ask.
Reply:Send them an email. But then again you never know if it they will read it
Reply:If I send a message to someone, how can I tell if they've received and read it?


Yahoo! Mail does not currently offer a return receipt feature.