If we want to keep email as open as it used to be, we have to be very inclusive. This is where reputation systems come in: just as credit bureaus tell financial institutions if someone is likely not to pay their bills, reputation systems tell mail receivers if someone is likely to be a spammer. Reputation systems are essential to solving the first- contact problem, but that is a topic for a different article.

This is notable, but its more a manifesto then an idea.

Internet Governance: An Antispam Perspective