writes "The Inquirer reports: Microsoft contemplating charging for emails. 'MICROSOFT IS UNFOLDING something it calls the Penny Black project in which people sending emails might have to pay for the privilege.' Microsoft's explanation of the project is here: The Penny Black Project."
There are a lot of things going on at Microsoft Research -- no guarantee that particular ones are going to be released in the real world. (And Microsoft isn't the only party interested in sender-pays, or at least sender-risks-paying systems.)