Some were pranksters, too. In the 1970s, before they founded Apple, Steve Jobs and his buddy Steve Wozniak figured out how to break into telephone systems and make free phone calls. In one infamous prank, the two Steves dialed up the Vatican to find out who would pick up.
"Wozniak pretended to be Henry Kissinger wanting to speak to the pope. 'Ve are at de summit meeting in Moscow, and we need to talk to the pope,' Woz intoned. He was told that it was 5:30 a.m. and the pope was sleeping," writes Walter Isaacson in his recent biography of Jobs.
It wasn't until the 1980s and '90s that hacking took a bad turn. Some blame Robert Morris, a computer science student who discovered a vulnerability in the Internet's inner workings and unleashed the world's first computer worm in 1988.
"He essentially brought the Internet to a grinding halt," says D'Ovidio, the criminal justice professor. Morris was the first person charged under the federal Computer Fraud and Abuse Act that had been enacted two years earlier.
Then came movies like 1983's "War Games," which also fueled the public's fear of hacking. In the film, a hacker unwittingly comes close to starting the next World War, thinking it's all a computer game.
"It happened because of Hollywood and because there was no other word out there," says Andrew Howard, 28, a research scientist at the Georgia Tech Research Institute. "Hacker is a cool word, right? It's a neat-sounding word."
The '80s and '90s were also a time when computers spread from geek circles to office cubicles and home desktops. They were becoming mainstream. But they were still mysterious to most people. They wondered: "How do they work? Is someone going to break into them?"
Zuckerberg's hacker manifesto is a nod to Levy, who codified "The Hacker Ethic" in his book about the subculture. Among the principles: "Hackers should be judged by their hacking" and "Always yield to the hands-on imperative."
The hands-on imperative is important to Facebook. Zuckerberg still spends hours writing computer code, even though he has hired hundreds of engineers.
That ethos helped Zuckerberg's social network to prosper. As the once mighty MySpace stopped innovating, its users flocked to the cleaner, crisper, always-changing Facebook. News Corp. gave up on MySpace and sold it for $35 million last June. Meanwhile, Facebook's user base ballooned to 845 million, even as the website has gone through changes and redesigns that have angered members and privacy advocates.
Zuckerberg and others may yet be able to clean up the term. Meetup's Hamblen thinks it's already happening.
"People aren't as afraid of technology, which was driving the fear of hackers," he says. "It was someone doing something with software that you don't understand. As people become more comfortable with technology in general, then hacking becomes a way of seeing it as using it in a clever way."
Technology companies, from the tiniest startups to those such as Facebook and online game maker Zynga, take the hacker ethic to heart. They host regular "hackathons," where engineers pull caffeine-fueled all-nighters writing computer code, usually working together on projects that are not part of their day-to-day jobs. Some of Facebook's biggest features, including chat, video and the new Timeline, came out of these hackathons, as Zuckerberg explained in the filing.
"Hackers believe that the best idea and implementation should always win — not the person who is best at lobbying for an idea or the person who manages the most people," he writes.
This is the ethic that can lift fresh-faced college grads (or dropouts) to the highest echelons of the technology elite, or at least to a good job.
Cadir Lee, the chief technology officer at Zynga, the company behind the biggest games on Facebook, says he "absolutely" refers to himself as a hacker. Lee says, at Zynga the hacker way means being agile. It's not the end of the world, say, if a game isn't perfect when players first see it, or if it has a bug that needs to be fixed. Think of it as live TV, Lee suggests.