"Spam, Spam, Spam, Spam, Spam, Spam, Spam," to quote Monty Python. Last week, I wrote about the so-called Internet advertising business and how its only real success is spam — unwanted bulk e-mail. I concluded that spam wasn't going away and might be less awful if it worked better, targeting only the people who actually want Viagra for $6. So the solution is to somehow improve spam. "Not so fast!" said several hundred readers who took me to task for legal, cultural, economic and psychological reasons. At least they all acknowledged that spam is a problem — a problem we'll try to solve this week. My intended column on TV advertising will have to wait another week.

My goal with this column is to give you a gist of reader responses in the last week, any new information that has come up, then go for the boffo finish in which I explain in some detail my intended solution for the spam problem. Alas, other than some specifics of implementation, my solution has been suggested by others many times before.

Any number of U.S. Constitutional scholars — most of them from Canada or the UK — piped-up to say that there is no free speech issue with spam since it is commercial communication. Tell that to the folks who send me political spam.

Some readers disagreed with me and wanted to outlaw spam entirely, but how does the U.S. or any other country outlaw spam in Russia, where much of it comes from? I don't think this is practical or wise.

Other readers thought the answer was simply to outlaw forged e-mail headers, but the Russian problem still remains, and plenty of spam arrives with perfectly legitimate headers. And if headers were somehow made illegal, you know the spammers would quickly work their way around that problem.

Several readers recommended various e-mail tools like NEO, SpamNet, and Spamkiller. These are helpful — sometimes VERY helpful — but Spamkiller doesn't let e-mail from me through to my friend Mario or to my own Mom. I don't take rejection well.

The most interesting comments came from people who had real ideas about the spam phenomenon and why it is the way it is.

"You say that the reason there is so much spam is because it's so effective," wrote one reader. "I don't know how you measure effectiveness in this case, but if I understand your reasoning, it's successful because if it weren't, it wouldn't be the phenomenon we know as spam. I find it hard to believe that there is a better way to persuade people to buy Viagra or second mortgages 15 times a day. The problem as I see it is that there is virtually no barrier to entry. A major part of the spam industry seems to be get-rich-quick schemes, often involving one spammer selling do-it-yourself spam businesses to new spammers. Because suckers are born every minute, and one spammer can inundate a large population of innocent email customers like you and me, and because it's cheap to get started, no one ever needs to make money, because it really doesn't take that many suckers to keep the ball rolling."

Another reader took this idea even further, pointing out some research that indicates that much of the spam business is used to support the selling of spam lists, not products. "While I agree with your assessment of the harm that spam causes to the infrastructure of the Internet and the cost of dealing with it, I don't believe that the majority of spam is a form of ‘advertisement’ used to market products. The commercial spam economy is based on the sale of e-mail databases and not consumer products. The proliferation of spam, which gives the impression that it is ‘incredibly successful,’ isn't a result of product sales. Spammers are not looking to sell you anything. All they need to make money is your address and some level of confidence that there is a person on the other end."

But let's say we somehow make spam better targeted, what then? "At this point we have a new problem," this same reader continued. "Once spam is targeted effectively, people will get a lot less of it. The spam that they do get will be a lot more attractive to them. Why is this a problem? Because people are generally used to shopping at brick and mortar stores. If you buy something from a brick and mortar store, or even from their mail-order catalog, you usually don't run into any serious problems. Now imagine a world where people actually read their spam and respond to a significant percentage of it. This would be a prime feeding ground for scam artists. If a person in this future setting receives ten ads a day for a particular widget, I would wager that only seven of those ads are from legitimate businesses."

But the biggest problem with spam, according to many readers, is that it is simply too cheap to do at all, so there is little need for spammers to do it well. "I was once involved in direct mail solicitations," wrote another reader. "Despite what you — and everyone [else] — think about junk mail, mailers actually work very hard to ensure that mailings only go to people who are interested in the product. You can't put anything in the mail for less than about 45 cents, and any kind of good offering, with color and decent paper and an easy way to reply, will cost you a buck and sometimes a lot more. Economic reality forces you to target your mailings carefully. With the same economic constraints in place, most of spam disappears."

NOW we're onto something! Make spamming more expensive to force spammers to be more efficient. This would have the effect of not only decreasing the volume of spam mail; it would also force spam to be used only for solicitations that could generate significant revenue, which might eliminate some of the currently popular spam topics.

But the trick here is not to do this by passing a law because laws can't generally be enforced over national borders. The only behavior any of us can reliably alter is our own, so WE — not the spammers — have to do something different. My proposed solution is a new class of e-mail application that combines many of the attributes we see on eBay, the Internet's one great commercial success. In fact, this solution could well be OFFERED by eBay, and I recently suggested it in an e-mail to Max Levchin of eBay's PayPal subsidiary.

What I am coming down to is essentially an economic argument. I think that passing laws is the wrong way to handle this problem and the right way is by making the spammers pay — literally pay — to reach me. I find preferable the idea that spammers pay me directly rather than have them pay the equivalent of postage that doesn't benefit me at all except by reducing the volume of spam. Of course, doing this requires a micropayment system, which made me think of PayPal, which can efficiently handle tiny transactions and already has 17 million customers.

What I suggested to Max is something I'll call PayPal Mail, which is very different from Hotmail or Yahoo Mail. Individuals or organizations sign up for this service, which uses your existing e-mail address, but passes all mail through an external server run by a company like MessageLabs, which already does this to scan e-mail for viruses and objectionable content before it ever reaches a corporate or ISP mail server. There are other companies in this same business, but I have written before about MessageLabs and am familiar with how their systems work. At the MessageLabs server, the mail is scanned for viruses and filtered for unacceptable content, etc. That describes the current MessageLabs service, but I would take it a step further. Referring to a database that reflects the user's e-mail address book, the filter would allow through mail from anyone in the address book. Any mail from senders who were not in the address book would get a message from the server saying "You are unknown to this recipient. If you wish to have your message delivered it will cost five cents, payable only through PayPal." Five cents is just a suggestion. The price could be anything and could even vary. Bill Gates could charge $100 and get even richer. Or using content filtering I could charge five cents for some messages and $5 for pornographers.

The beauty of this system is that it uses economic forces to control spam, forcing spammers to target the folks they really want to reach while vastly reducing the total volume of spam. Forged e-mail headers won't make any difference. And everyone doesn't have to use it for this system to be effective. Only I have to use it if I want to be protected, but if enough people use it then spamming will be changed for everyone.

Of course, this system also makes recipients and spammers alike join PayPal. That ought to be enough of a reward for PayPal (eBay) to offer the service for free. For most people, their payments and receipts would probably balance out, so only the spammers would really be paying, which would create the equivalent of postal junk mail except in this case the postage goes to the reader, not to the Post Office.

I like that.