Around age 13, he discovered the website FlyerTalk, a massive free-for-all forum of all things airline, where users meet to strategize over deals, test for cracks in the bureaucracy and share the spoils.

... FlyerTalk became the singular worldwide hub of airline nerds, and today it claims to have more than 500,000 members. Virtually nothing on FlyerTalk is meant to be understood by outsiders. Posts there are littered with jargon like "3xx" (Airbus), "open jaw" (three-segment round trip) and "FEBO" (in-flight meal delivery).

... Airline representatives insist ... FlyerTalk represent little more than a portal for passionate customers. But mention the Hobby's darker side, and they turn grave. "If any members of these groups were particularly effective, they could have a catastrophic effect on an airline," says Jonathan Clarkson, director of Southwest Airlines' rewards program.