my-online-drugstore.com, Preapprovedrx.com, Matrixmeds.com, and 123onlinepharmacy.com. Not all of the sites were necessarily owned by RX Limited directly. Many of them appeared to be what are called "affiliates": a kind of marketing front that independent contractors on the Internet could set up and use to attract drug- buying customers, who were then funneled into the RX Limited network.

To attract affiliates, RX Limited offered a premade website and the promise of a 60 percent commission on every sale. Those com- missions were coordinated through sites like RXPayouts.com, Netbizbucks.com, and Pillengine.com. "Open your own online pharmacy," the banner atop RXPayouts.com proclaimed. "The RXPayouts.com Affiliate Program is the premier pharmacy oppor- tunity on the Internet." The affiliates' marketing strategy seemed largely to involve sending spam email to massive mailing lists, and gaming search engines so that a site like Your-pills.com would ap- pear atop the results when someone searched for a particular drug name on Google.

The websites appeared to offer a wide range of drugs, everything from Propecia, the antibaldness pill, to generic forms of Viagra. But when Brill and Holdren started digging into the pharmacies' records, they discovered that the vast bulk of RX Limited's busi- ness derived from three specific drugs. The first, Ultram, was the brand name for a synthetic opioid called tramadol, which-like the better-known opioids OxyContin and fentanyl-was develop- ing a reputation for abuse, although largely outside of the United States. Soma, generic name carisoprodol, was a muscle relaxant often prescribed for back problems. And the third, Fioricet, was also often prescribed to treat tension headaches and migraines. In addition to being powerful painkillers, the three drugs shared an- other property Brill and Holdren realized was crucial to RX Lim- ited's scope: None were considered "controlled substances" by the U.S. government.

Dictated by an ever-evolving law known as the Controlled Sub-