Can you imagine if USPS ran an email service and all of the legal protections afforded to our mailboxes and the contents of our postal communications applied just the same? The internet would be a completely different place. In a good way, I think.

Less awesome, but realistically USPS and their respective national organizations should run their DNS RBL lists. Protecting their nations against spam.

If the USPS ran email, they would legalize spam and charge by the kilobyte.

Is spam illegal now?

Can you imagine if all of that was true except that it could be run by anyone? (Sadly, we have very little -- almost zero -- legal protection for our email in the U.S.)