A protocol-based method for email forwarding by an email server is
performed as follows. An initial email is received from a sender, and
checked to ensure that the initial email includes a reusable electronic
paying means. If the initial email carries a reusable electronic paying
means, the initial email is forwarded to the recipient. An acceptance
email containing a reusable electronic paying means is later received
from the recipient of the initial email, and forwarded to the sender.
Email not carrying an electronic paying means is rejected.