Does Mail.app send or can request read receipts? I was wondering whether Mail.app is able to send read receipts (or maybe it does silently?) or create emails that require those?

I know such a feature is available in Outlook.
I tested this using Mail on Snow Leopard connected to Exchange 2005.

There is no ability to set a request to receive read receipts.

Reading an email sent from Outlook in Windows to mail on Snow Leopard with a read recipt requested, does not send a read receipt.

Lion may vary.