Spam Works

Every day three-quarters of all e-mail that flies across the Internet is spam. Some of it tricks customers into installing a virus or forking over personal information to use illicitly. But many spam messages are advertisements for companies that sell real goods, usually prescription drugs, knock-off watches, and pirated software. Millions of Americans see it as a way to save on drugs. “You pay the money, and you get a product,” says Stefan Savage, computer science professor at the University of California, San Diego.

Over several years, Savage has helped bring together a team of more than a dozen researchers at UC Berkeley and UC San Diego to try to understand the economics of spam. Among their findings: A surprising 91 percent of purchases are ultimately delivered, but the “Viagra” mailed to you may not contain the correct dosage or even the right active ingredient.