JuVDC
Here is a good example. Let’s say you have a form on a website that users fill out and you want those to create tickets. From that site let’s say you send that form as an email from a generic address to your system to create tickets. If that ticket comes in the user will be the generic email you sent from rather than the users real email. You can include their real email in the Reply-To header and use the Filter Action to use the Reply-To which would then create the ticket for the real user.
Cheers.