Post #4 on Why Spam Filters Suck “trickle blog” seriesApril 11th, 2008, by d.liao
“Spamonomics”: The Economics of Spamming
Spammers earn billions of dollars annually. The business is efficient, hierarchical, and organized. In much the same way that the global trade in narcotics involves every conceivable method of smuggling (from submarines to drug mules), the spam trade employs software engineers to develop increasingly sophisticated delivery technologies. Just as the drug trade will continue until the end of humanity, so too will the illegal delivery of spam.
To understand how spamming has become such an intractable problem, it serves to analyze the economics that drive spamming. Spammers make money if one in every 30,000 recipients makes a purchase. And given this response rate, a spammer advertising pharmaceutical products can expect to make roughly $5,000 per million email messages sent.
Finding out what it costs to send spam is not difficult: Botnet operators advertise their spamming services via online forums. One forum mentioned a price of $100 to send one million spam messages. If we assume that $100 is the cost per million spam messages, and $5,000 is the revenue, then the gross margin from spamming is approximately 98 percent.
Although some spam filters provide better accuracy than others, filter accuracy across the board is approximately 90 per cent, meaning that only one in ten spam messages reach a recipient. If global anti-spam effectiveness could be improved from 90 to 95 per cent, earning $5,000 from spamming would require sending 2 million spam messages, rather than 1 million. This increase in volume would reduce the spammers’ profit margin from 98 per cent to 96 per cent assuming sending costs remained constant. If global anti-spam accuracy reaches 99 per cent — a figure that experts will tell you is nearly inconceivable given the innovative methods of spammers — sending costs would reduce spamming margin to 80 per cent. Google is one of the world’s most profitable advertising companies with a margin of 25 per cent — imagine 80 per cent? This is a business that won’t be going away any time soon.
Before botnets arrived, spammers could be stopped by blocking their IP addresses. DNSBLs like Spamhaus and Habeas block between 60-70%. With the introduction of botnets, blocking no longer provides a sufficient solution to the spam problem.