In 2006, Congress tried to crack down on illegal online sports betting. Nearly a decade later, Internet gambling is flourishing, and a new business that increasingly looks like gambling, fantasy sports, is winning millions of players and stoking controversy. For this week's Please Explain, we talk to James Glanz and Walt Bogdanich, part of the New York Times investigative team that, with the PBS series "Frontline," investigated the business, and the technology, of illegal gambling in the Internet age.