It would be very convenient to be able to reply to mail people send you via the big boxes through the small ones. Well, that's kind of obvious but still. =)
A desperate plee...
But maybe... when sending from a dispatcher, you can check a Pay for Response. 50C for normal, 150 for express. This would be payed right away and if the person DOES not reply... THEN CURRANT GONE FOREVER. (the pay for response only lasts for 24 hours after opening the mail or something).