I take that back

I've often wondered what it would be like if there was a software program that could reveal the changes that had been made to a received e-mail before the author had clicked 'Send'. An unspoken-word editor, so to speak.

What words did the sender decide not to send? What was I not supposed to know? It would certainly wreak havoc on on-line communications. But I didn't necessarily say it was a good idea... just an idea. And why haven't they invented transporters yet? I'm still waiting!