Gary Eisenberg has climbed mountains in Sri Lanka and scuba dived in Thailand. He has worked in a boatyard in Turkey and bartended in Portugal. He has roamed Egypt, Morocco and New Guinea. Yet this seasoned traveler--who globe-trotted for a decade before settling (at least for now) in New York City as a corporate lawyer--rarely takes a guidebook along. "As soon as a place gets listed," he explains, "everybody goes there. The quality drops, and it is hard to get in."
Instead, Eisenberg, 39, relies on online travel forums for advice. While printed guides may offer good cultural and historical information,...