There's a vintage Saturday Night Live bit where Al Franken, pre-U.S. Senate, plays a one-man band of media. He's wearing a satellite transmitter on his head and holding a mic while reporting live for SNL's Weekend Update. This image of Franken comes to mind as Craig Newmark—the Craig of Craigslist.org—is conducting a magazine interview at the same time he is snapping digital photos of a hummingbird in his backyard. Immediately after the interview, he will post the bird on his Facebook page. Seconds later, he will e-mail a "thank you" to his interviewer.

Newmark, 56, of San Fransisco, not only Facebooks, but blogs and tweets. He is all things to all of the new media. He also handles customer service for Craigslist, the online trading post giant he created where you can find anything from a free fridge to a date for Saturday night.

Today, the market value of the company is estimated at $1 billion. Yet the for profit company is not motivated by profit, Newmark says. "We just have a very odd business model. Our business model, in a sense, is we can do well in business by doing good for people. We don't run MBA style."

Newmark founded the company in 1995 as an e-mail list of San Francisco social events sent to his friends. Later that year, he launched the first community site for San Francisco.

Born in New Jersey, Newmark originally studied to be a physicist before switching to computer science. He went on to receive a master's degree in computer science from Case Western Reserve University in Cleveland and started his career at IBM, where he worked for 18 years. He also was a programmer for Charles Schwab, Bank of America and various consulting firms.

In early 1999, he gave up software contracting and went full time with Craigslist. It wasn't much of a leap of faith for Newmark. "Since I live simply and am pretty frugal, it wasn't an issue financially. Also, I had rather marketable skills," he says. He also hired Jim Buckmaster as CEO, and credits him for the company's effortless success. Buckmaster, then an unemployed Web programmer, got the job by posting his r´esum´e on Craigslist.

Craigslist is privately held and doesn't disclose financials, but one study, from the Classified Intelligence Report, estimates the site will conservatively generate $100 million this year, a 23 percent gain from last year's estimate. With Craigslist's success, you understand the reach and breadth of the Internet. The low-tech site, with listings and occasional photos, is able to hit an estimated $100 million with advertising that is free to users in more than 570 areas in 50 countries, except in 17 major U.S. cities, such as New York, Los Angeles, Dallas, Atlanta, Portland, Seattle, etc.

Craigslist charges recruiters $25 in the major cities, $75 in San Francisco, for help-wanted ads. The company says the recruitment ad charge wasn't designed to generate profit, but to deter scammers who posted what sounded like real jobs but were actually work-at-home, stuff-envelopes-type cons. In New York, real estate brokers have to pay $10 to post individual housing listings. The company also charges for adult service ads. Craigslist says money from that category is donated to charity.

To understand the significance of Craigslist's achievements, consider that the site is consistently ranked in the top 10 in page views for English language Web sites, with Google at No. 1, according to Alexa, a Web information company owned by another online giant, Amazon.com.

Then, consider that Craigslist has just 30—yes, 30—employees, working out of a Victorian house in San Francisco, managing more than 570 classified-ad sites in 50 countries. Google has nearly 20,000 employees; other companies in the top 10 have nearly as many as Google.

Craigslist can accomplish so much with so few employees because it operates under the Golden Rule, Newmark says. "We believe that we should treat people like we want to be treated, and that applies to employees as well as customers."

When Newmark says he's been working four hours every day on Craigslist's customer service and four to six hours on his volunteer or public service work, he means it. "Speaking as a nerd, part of the dysfunction is we're very literal. Every day is every day," he says. Seven days a week? "Yes," he says.

Philanthropy is part of Newmark's "iconic responsibilities," as the company calls it. He does it because "it feels right." Craigslist reportedly gives away 1 percent of its profits, and Newmark, personally, is active in a variety of causes from veterans' rights, to Middle East peace, to good government and investigative journalism. Newmark's contributions can be both financial as well as active, and he's interested in using the power of the Internet to ramp up grass-roots efforts for the causes he supports. "Mostly, they want me for two things: Help them work on social media, Facebook and Twitter, and help them get the word out better on what they're doing. I figure I can help."

In his blog, Newmark explains his role with charitable causes: "Like most humans, I'd like to save the world, but I figure I need a nap. So, I figured it'd be much easier to talk you into doing it by talking up the efforts of people who are really effective at helping others."

And that idea of helping others extends to the site, as well. Because he is in customer service, Newmark doesn't hear too much of the good stuff, but knows the company he founded helps people find jobs, romance, furniture, lost pets—what have you. He knows of five kidney donations and a number of marriages brokered through Craigslist. Its job listings typically get 51 replies, No. 2 after CareerBuilder.com, which gets 69 replies, according to a 2006 Yahoo Finance report.

But the site does more than let people exchange goods or services. It's also a social network, with discussion boards, rants and raves, missed encounters and the like. And not only does the site allow users to self-publish ads but self-police as well. Users will turn in scammers and listings that violate the site's terms. And those listings get pulled.

Before Craigslist, Newmark was more skeptical of people, he says. Founding the company "eroded my cynicism. I see that people are overwhelmingly good. Our culture is self-policing."

His goal for Craigslist is to do more of the same. "The deal is we do a good job of some things. We need to keep doing it," he says. "We do a great job of classified ads in a culture of trust."