We're learning more about the hundreds of Internet sites that advertise or sell controlled medications by mail. Yet a new set of answers brings a series of worrisome questions: How many of these websites actually require a prescription for controlled substances? Do many of those who buy prescription drugs online do so with nefarious intentions? Dr. Charles Turck probes problematic developments in online drug sales with Susan Foster, vice president and director of policy research and analysis at the National Center on Addiction and Substance Abuse at Columbia University. Ms. Foster directed the preparation of the Center's most recent You've Got Drugs report on spurious drug sales on the Internet.