Let all communication with users flow through the map. Use temporary email addresses for this purpose. For example an address like mapreply484u59823@map.thelastreformation.com. The map software than makes sure the email is forwarde to the right user.
For different reasons. One being: if you don't fully trust the sender of the message yet and want to learn more, it would be great people can communicate without giving away their identity right away. Or for more closed countries, this could be an important feature.