This week’s splogstorm and the endless flood of email spam are two symptoms of the same disease. When you allow people to add content to the Net for free, the economic incentives to fill all the available space with with spam are irresistible, and fighting back is difficult, maybe impossible. This works because, while the payoff per unit of spam is low, the cost is zero. Well, we can solve all these problems at once. It wouldn’t be free, but it would be cheap and it wouldn’t be that hard. It’s called “Internet Stamps”.

Buying Stamps · Let’s assume, for the moment, that Internet Stamps are provided by a few law-abiding countries’ Post Offices (the U.S., Canada, Slovenia, whatever). They’re not the only candidates, but they have the right characteristics and it’ll keep the discussion concrete.

An Internet Stamp is an assertion, signed by a Post Office, that some chunk of text was issued by someone who paid for the stamp. At least one major Post Office will be required by government statute to sell stamps to anyone in the world for either US$0.01 or €0.01, and no stamp-selling organization will be recognized which sells stamps for less than this amount. For this to work, the number of stamp-selling organizations needs to be small and the organizations stable; another reason why Post Offices are plausible candidates.

It works like this: if you want to buy stamps, you sign up for an account with your Post Office; it works like paper stamps, you buy a bunch at a time in advance, in small amounts like $20 or €10. Then the Post Office offers a Web Service where you connect to a port, authenticate yourself and send along some text; the Post Office decrements your account and sends back the stamp. There are a variety of digesting/signing/PKI techniques that could be applied to implement the stamps; a standard is required but should be easy.

Using Stamps · So, you write an email, and when you press “Send”, your client calls up the Post Office, gets a stamp, and sends it along in a header. Similarly, when you do a blog post, the stamp can go in the in an HTML header <meta> element, and be stuffed conveniently somewhere in the <atom:entry> element. Remember, the presence of the stamp asserts nothing more than “somebody paid at least 1¢ for this”.

Then, you program your email reader to reject all un-stamped email (with some exceptions: for example, mailing-list traffic; but the mailing-list software wouldn’t accept un-stamped submissions). This requires a white-list of trusted stamping organizations, which has to be editable; if word goes around that the spammers have bribed someone at Deutsche Post and scammed a few million stamps, you knock them off the white-list for a while.

Similarly, feed readers could ignore un-stamped feed entries. This would be of use mostly to aggregators and search tools such as Technorati, PubSub and friends.

This could work for Wikis, blog comments, Usenet, you name it; anything where you want the general public to be able to contribute to the Net.

The Cost · For the law-abiding, it would be vanishingly small. I am a prolific online writer (email, ongoing), but my costs would never reach a dollar a day. For the spammer, a penny a pop is prohibitive. If a bank or airline or soft-drink company wanted to pay the price to spam me, I might get irritated and it might make me less likely to do business with them, but I just know I’m not going to be hearing from penis patch peddlers or Miriam Abacha.

As for the revenue... one assumes that this would run at a profit, but that needs to be proven. An advantage of having this done by actual public-sector post offices is that if the profits are substantial, they could represent public revenue and thus provide tax relief.

Anonymity · Why not? If someone wants to buy stamps for cash, I’d say go ahead and let them. There might be a case for a value-added system whereby you could arrange that the stamp asserts not only that you paid but that you are the owner of some particular email address or URL, but there is value in anonymity. And anyhow, we’re just trying to solve the spam problem, not the identity problem.

Provenance · This is not my idea; it grew out of a discussion at the first Foo Camp with Jeremy Zawodny, Dave Sifry, and Doug Cutting. Later, Microsoft Research’s Penny Black paper proposed a similar idea, only you pay in units of computation rather than currency. I think currency is easier to understand.

author · Dad · software · colophon · rights
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October 16, 2005
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