MSGTAG Free alerts you the moment an e-mail you've sent is opened. You'll know when the message was sent, when it was viewed, and the elapsed time in between. The beauty is that you don't have to change anything about the way you write or send your e-mail. In fact you'll hardly even know it's there - a small icon in your system tray is the only indication that it is working quietly in the background. It works with almost all desktop e-mail clients including Outlook, Outlook Express, Eudora and Pegasus Mail. It runs in the background while you send your e-mail as usual. This means that you don't have to write your message into a strange little box, or alter email addresses before you send anything. One of the best things is that your friends don't need to do anything different either. There are no annoying pop-up windows asking them to send a notification back to you - all they see is a small footer stating that you've been notified of them having received the message.