Welcome to Craigslist.org, the free classifieds site now evolving into an unprecedented virtual community. Here, users carpool to save gas. Some find jobs. Others trade vacation properties to avoid hotel fees. And that’s just the beginning.

“About six months ago someone lost an iPod on the Boston light rail. Someone else found it. They connected through Craigslist.org,” site founder Craig Newmark says. “Somebody got back their iPod. I like that a lot.”

Newmark is talking on his cell phone from San Francisco, his company’s base of operations. Short and wearing thick glasses, Newmark says he has never thought of himself as a revolutionary. Now, Newmark sits at the helm of the world’s most popular online classified Web site. Newmark, a self-professed geek who once considered posting a personal ad on his own site, stands between Steve Jobs and Martha Stewart on Time magazine’s 100 most influential people list.

From Bangkok to London, Sao Paulo to Phoenix, about 10 million users log onto Craigslist every month. They’re finding everything from life partners and lost pets to plumbing solutions and bartering for some dental work.

Up for trade today in the Valley is Scottsdale resident and business owner Joseph Verdone’s 700-horsepower Corvette Z06. He’d like to trade the $50,000 sports car for an in-ground swimming pool. “Because of Craigslist, people are realizing they have services and products that can be traded,” Verdone says.

Verdone has been using Craigslist for about two years. In that time, he hasn’t paid a cent for hours of landscaping, masonry and painting chores around his house. Rather, the custom auto accessory shop owner trades for accessory work on vehicles.

Verdone’s Corvette barter proposition is just one of hundreds listed on the Craigslist.org Phoenix page today, and the barter section is small beans compared to job postings (9,120 in Phoenix) and housing (17,869 Phoenix listings).

By the People, For the People

Unlike other top-10 Web sites, Craigslist is virtually free of pop-up and banner ads. Users pay nothing for the service, ever. Where daily newspapers charge for classifieds and limit users with space and time, Craigslist ads are not restricted in length and are as free as the air you’re breathing.

“Everything is based on what people have suggested,” Newmark says. “People suggested stuff like job postings or stuff for sale. I responded by putting them in. In a way that’s our whole history. People suggest stuff, and we do it.”

Phoenix landlord Jody Gnant says that user-driven community is exactly why she uses Craigslist. “They don’t make me fill out what my zip code is, what my age is. I don’t have crazy pop-ups. They don’t have to take anything from us. People in return are offering what they have in exchange.”

Gnant found her last two years’ worth of tenants through free Craigslist postings. “They’ve been great tenants,” says Gnant, who also searches the barter section daily for noteworthy trades.

“Right now I have an ad up for a keyboardist for my band,” she says. You may recognize Jody Gnant’s name from her most recent barter transaction, one year of free rent for a recording contract and a famous red paperclip.

Gnant’s trade was one in a series of escalating barter transactions that began with a red paperclip offered on Craigslist. Oddly enough, daily newspaper accounts of the story mysteriously failed to mention the name of the site on which it all started, Craigslist.org.

The Revolutionary

At a recent American Society of Newspaper Editors convention, directors flashed Craig Newmark’s mugshot across the big screen. “Do you know this man?” they asked the editors of the largest newspapers in the country.

Newmark, a former seventh-grade computer geek, is now well-known by these editors, and for good reason. His Web site is the coffin-closer for the daily newspaper classified ad cash cow. Publishers fear for their profits. Journalists fear for their paychecks.

More than free classifieds on electronic steroids, Craigslist is evolving daily into an unprecedented and unpredictable digital community. Nobody really knows how far it could go. Gnant, among others, cites a personal connection and trust among users. “If everybody knew about Craigslist, would the people who reply be as cool? I don’t know.”

As the masses increasingly embrace the concept, companies spanning all industries could feel a major impact from such Web-based shockwaves.

If Craigslist is indeed a virtual democracy, then Craig Newmark is the revolutionary at the helm, which wherein lies the irony. While dotcom sites were investing millions before the dotcom bubbles burst, Newmark was quietly giving people what they wanted, for free.

Now his site, which he touts as having been designed by the people, for the people, boasts a GDP and a population that eclipse some small world nations. Users rejoice that there still aren’t any taxes. Industry experts estimate Newmark could cash in on about $550 million a year if he started selling ad space on his site, but Newmark insists his list is for community use, clinging to his quasi not-for-profit status.

As the years have passed, more analysts have come to believe Newmark really isn’t in it for the money. Newmark’s biggest Craigslist deal lends some credibility to that notion. It was the purchase of his 1992 Saturn. He now says he drives an eco-sensitive Toyota Prius, lives in an apartment and runs his business from an old house in San Francisco. This coming from a man whose name may ultimately appear next to Bill Gates and the founders of Google in the annals of Internet history.

Today, the deep-voiced San Franciscan tells about his recent trip to New York. It turns out the employees at the Tribeca Grand, the hotel where he stayed, had all landed their jobs through his site. He says these are the kinds of things that excite him, not money.

“I never had a clue Craigslist would be so big, and I still try to behave like it’s something that needs continuous nurturing,” Newmark says.

After deciding that a personals ad on his site would pose a conflict of interest, Newmark met his girlfriend at a local café. The story is telling of Newmark’s life philosophy, “Treat others the way you want to be treated, and things will work.”

“The big theme is a culture of trust,” Newmark says of Craigslist. “The idea is that we all share some values. The culture of trust and the golden rule feed into each other. People are overwhelmingly trusting on our site.”

Gnant agrees that the culture of trust and shared intelligence offers unprecedented opportunities. “I think Craig made the people important. He put the people above advertisers and dollars and cents,” Gnant says. “Craig put people first, and Craig is succeeding for it. If you talk to him, thank him for not subjecting me to pop-ups.”

Back on the phone, Newmark says he’d better get going. He spends 40 hours a week personally fielding customer service inquiries, and he’s gotten a little behind on his hours this week.

“If you all of a sudden have a question, just call me. I know how frustrating it would be if you couldn’t get a hold of me,” Newmark says. “Have fun with the story. I’ve got to get back to customer service.”

If this were an election to name the person to head up such an important online community, it’s pretty obvious after a short discussion with Newmark that we’d have to vote to keep him in office.

I know at least one journalist who would vote for Newmark. Apparently, about 10 million other monthly users would agree. Hey, Craig, if all the newspapers are dead in five years, can I come work for you?