Mail App on Mac OS X Lion has a feature that allow users to redirect message. When you redirect message, the recipients will have the from address of the original sender and not yours. Let us see the difference between forward and redirect with some screen shots
Clicking the Forward Message will have your email address in the From column. A Begin forwarded Message text will be inserted before forward email content.
You can use this option when you want to add your comments (more information) to the forwarded content.
This will display your email address in the From column but the Recipient of the email will only see the Original sender email address in the From column and your email address in the To column.
You can use this option when you do not want to make any changes to the content and forward the message on behalf of the original sender.