Spam
Perhaps a good way to end spam is to associate a cost with emails. If each email cost 5c to send but the 5c was refunded upon acceptance from the other end it just wouldn’t be affordable to bulk-mail a million emails. You could have a number of accredited companies where you could pre-pay say $10 or so and top up from time to time. It’s good for the top-up companies because they get a bit of money to play with and it’s good for everyone on the new email system because they get less, much less, spam.
