Computer hackers of today set their sights on credit card information and other valuable intel that can be sold on the black market or used directly. But, Kaminsky said, in the early days of the Internet, hackers were often just trying to maintain long-distance friendships.
"Until recently, a major motivator was, 'I have friends who live far away, and I want to talk to them," he said.
That motivation gave rise to a high-tech subculture of "phone phreakers" who learned how to take control of the phone network to give new meaning to the prank phone call.
In one legendary case, he said, phreakers hijacked all incoming calls to a Southern California city in the early 1970s and said it had been leveled by a nuclear explosion.
On his Web site, John Draper, aka Captain Crunch (one of the more prominent phreakers), references an attempt by Apple co-founder Steve Wozniak to reach the pope via phreaking and pretending to be Secretary of State Henry Kissinger.
"There have been pranksters for as long as there have been people," Kaminsky said. "And whatever technology is available to have a little fun is certainly going to be used."