"Some people think I don't exist."

That's hard to digest. He's a pseudo-celebrity here, worthy of a one-name moniker: Craig, as in Craigslist.org, the free-for-all utopia that is the Internet's most frequented bulletin board. It's a Yellow Pages for the 21st century, a staple of everyday life in New York, Los Angeles, Boston -- and, increasingly, in the Washington area, with more than 40 million page views per month.

On Craig Newmark's site, you can trade your futon for a leather couch, find your two-pound Chihuahua a film role, rant about your ex-boyfriend while looking for a new one.

Everyone is equal. Everything is possible.

"I think it proves that, basically, people trust each other," says Craig, who often punctuates his sentences with a sigh. He's the shy, self-deprecating type, sipping mineral water at Canvas, the part art gallery, part chic cafe that is drowning in a sea of Wi-Fi-connected laptops. "People want to get along."

Or so Craig -- idealistic as he is -- hopes.

For a while, the site that bears his name was a mere reflection of a do-gooder who wanted to "give people a break." But, lately, as its popularity has grown, Craigslist has become bigger than Craig -- more Our List than Craig's List -- revealing more about us and how we live than about the man who invented it.

Is Craig a super-computer, sitting somewhere smack in the middle of Silicon Valley?

On a recent Sunday stroll in Dupont Circle, a group of 25-year-olds ponder aloud.

"I never thought of Craig as a person," says Laura Kolar, looking a tad embarrassed.

Chris Deutch nods. "I just didn't bother to think about it."

Shu-Ping Shen shares this: It was August 2002. He was in New York City, living on the Upper West Side, and he needed someone to take over his lease. So he posted an ad on Craigslist. "Two seconds later," he says, "I got more calls than I've ever gotten in my whole life."

The three laugh it off.

That instant gratification is a familiar experience for anyone who uses the site -- especially transient twentysomethings (and thirtysomethings and fortysomethings) who socialize as much in bars as on the Internet. The site is refreshingly simple. No registration. No user names. No pop-up ads. Say you're looking to start a group, like the North Virginia Tall Club, a social organization that was posted for tall men (at least 6-foot-2) and women (over 5-foot-10). Then you go to Craigslist.org, click on the "wash, DC" link, click on "post to classifieds," click on "community," click on "groups."

This is all free. Craigslist, a private company that is worth upwards of $10 million, charges only for job listings in its three busiest markets, San Francisco, New York and Los Angeles, from $25 to $75. In the Washington area and everywhere else, job listings are free.

That's just the way Craig works. For the record, Craig Alexander Newmark is a native of Morristown, N.J., a 51-year-old portly man with a fondness for babies, dogs, Thai food and the newest gadgets -- like the Treo 650, a cell phone-wireless-Internet-digital-camera gizmo that's due out next month. He's "20 or 30 pounds" overweight and walks around with a pedometer. He is "committed to someone" and says, in jest, that his ideal woman is a cross between the fictional press secretary C.J. Cregg (Allison Janney's character on "The West Wing") and the nonfictional veteran Washington reporter Helen Thomas.

There's irony at work here. How can someone so "socially stupid" -- Craig's words -- start something like this? It was a way for him, he says, to connect with others.

The year was 1995. Craig, a recent transplant to San Francisco, started a list of social events and parties and e-mailed it to a small cadre of friends who, in time, e-mailed it to larger cadre of friends. The site took off. Now, barely 10 years later, Craigslist is one of the Web's top 20 portals, with 5.3 million visitors a month.

The Alexa rating service, the Nielsens of the Internet, says Craigslist is in the top 15 Internet companies in terms of traffic -- with more than 1 billion page views a month, it's right up there, elbowing Amazon.com. Its job listings section draws as much traffic as Monster.com. Its classified ads are more than 2.5 million a month. Recently, eBay.com, in what was a shock to the online industry, bought a 25 percent stake in Craigslist from a former employee.

There have been imitators -- most recently Cityopoly.com. So far, nothing has matched Craigslist's efficiency or grass-roots appeal.

In the past four years, as the dot-coms boomed and busted, Craigslist, with a staff of 14, has expanded to offer listings in 48 U.S. cities. It also has sites in nine cities in Ireland, Canada, the United Kingdom and Australia.

In this sort of online, laid-back democracy, trust is key and users get heard. The site's "flagging system" is proof of that: If you find an ad offensive, you can "flag" it, and with enough "flags," it will be automatically deleted from the site. Users can also suggest new sites (in cities like Anchorage) and new categories (like "collectibles").

The "wash, DC" site is the fastest-growing listing, increasing its traffic 300 percent in the past year, Craig says.

"I think Washington is a very networked city, in the human sense," he explains, sighing. "Once people saw that we're for real, very useful and effective, people told each other."

Craigslist, by the way, has never advertised anywhere. It's all word of mouth.

On Oct. 3, at 11:18 p.m., this ad was posted on "missed connections," the "I Saw You" personals on Craigslist.

"You walked through the hidden iron doors on Saturday night looking very dapper in your suit. It looked like you were with your family, possibly siblings. A pair of twins, perhaps? That runs in my family, too. I watched you talk about mail order frogs with some floosie. I wanted to share my love for amphibians with you as well, but it is so difficult with the secret service always following me around. Will we meet again on the corner of Wisconsin and O??"

Three days later, Ana Marie Cox -- wonkette.com herself, whom Craig Newmark credits for the surge in usage in the area -- posted a link of this ad to her site. She writes, "Being the president's daughter apparently has its downsides."

"I thought the posting was so funny," says Cox, 32. "Clearly, it was a thinly veiled parody of Jenna Bush."

Cox links to Craigslist frequently and finds the site fitting, "in a weird sort of way," to the D.C. crowd. "It's this nexus for staffers and drones and interns who are frustrated, bored, sitting at their desks doing nothing. There's something about the anonymity" -- the Oct. 3 ad, indeed, was posted anonymously -- "that must appeal to the paranoid D.C. type."

In fairness, not all postings are like this. The "wash, DC" site, after all, has more than 300,000 visitors a month, 80,000 classified ads a month and 4,000 new job listings a month -- adding up to more than 40 million page views a month, though keep in mind that folks post and re-post ads.

Like the Village Voice in New York and the SF Weekly and SF Bay Guardian in San Francisco, for example, publications like The Washington Post and the City Paper are facing stiff competition on classified ads. Those ads have been "a destination" for readers of the City Paper, says Sheri Simon, the weekly's classified sales manager. Still, how do you face off with a site that is updated by the second, 24 hours a day?

For one, the City Paper's Web site is moving toward daily updates, says Simon, who also surfs Craigslist, if only to look at the competition.

The name Craig is in honor of his great-grandmother, Cecilia. Joyce, Newmark's mom, says she wanted a name starting with a "C."

He was born on Dec. 6, 1952. Lee, his father, died of cancer when he was 13. He was that kid in Geometry who raised his hand too many times.

Then as now, "The people I identify with ethnically, if you can put it that way, are the nerds." He continues, with no trace of self-pity, "If you're a nerd, no matter where you are, no matter where you come from, you're a nerd."

He recalls a particular day in college, sitting in the school cafeteria, at a table, alone, reading the classic S.I. Hayakawa book "Language and Thought in Action." It was October 1972. He was at Case Western Reserve University near Cleveland, studying computer science. "I remember realizing, it couldn't be that everyone else had a communication problem. It had to be me."

For years he worked as a systems engineer for IBM. Spent six years in Boca Raton, Fla., 10 in Detroit, one in Pittsburgh. Then, on a whim, he moved to San Francisco. "It seems to have the right atmosphere," Newmark says of the city. "It's hard to define." He spent some time at Charles Schwab, as an "Internet evangelist" working alongside an "Internet pioneer," Darek Milewski.

Both men preached about the Internet -- how this medium would transform the brokerage business -- to empty pews. So they left.

"The thing that really fascinated me about Craig was his passion. Everything was a priority," says Milewski, now director of information security at Oracle. He is most impressed by Craigslist's business model. Craig, Milewski says, could be an instant millionaire if he sold the company, or if he tried to capitalize on it more: charge for, say, half the postings?

But, continues Milewski, "That's not his values -- he was never about money. Craig is a consistent guy."

Craig isn't the boss at the office. In a $4,000-a-month Victorian in the Inner Sunset, Jim Buckmaster, who at 6-foot-7 is a foot taller than Newmark, calls the shots.

"It's better that way," says Craig, sighing. He admits that he wasn't a good manager. He's too nice. "We try to run the company on a group consensus, and a number of people approached me and said the situation needs help."

Buckmaster, whose resume Craig spotted on Craigslist in 1999, was hired as a lead programmer. Buckmaster is the president and CEO, Craig the founder and chairman.

The two sit across from each other, sharing a room no bigger than 10 feet by 12 feet. Right now, Craig is glued to his 20-inch computer screen, reading DailyKos.com, a favorite site -- "I'm my own kind of Democrat," he says, "heavily influenced by Howard Dean" -- and switching over to Craigslist, checking out the blog he started nearly a year ago.

He checks his e-mail.

Craig has 16 e-mails in his inbox, Buckmaster 28,354. "Craig is a bit obsessive about e-mail," says Buckmaster, 42. "Funny thing is, he gets more e-mail than me."

The Craig of Craigslist takes it all personally.

He works seven days a week -- as one of four customer service representatives. "I've been disappointed," he says, "with the customer service operations of big companies." He gets more than 600 e-mails from users a day, not to mention dealing with five or six spammers a day, and, lately, with apartment brokers "trying to pull a fast one," posting ads in the no-fee requirement category of apartment listings.

He walks over to Canvas, the art gallery/cafe down the street. He checks his pedometer. From about 9 a.m. to 5:20 p.m., he's taken 3,809 steps. ("I have to do better," he says.)

Craig surveys the mostly young crowd typing on their laptops, all of them connected to the Internet, some actually on Craigslist. "I'd like the site to be everywhere," he says, "everywhere we are welcome."

Oct. 10 was proclaimed "Craigslist Day" by the San Francisco Board of Supervisors. That same day, the documentary "24 Hours on Craigslist" -- where an Ethel Merman drag queen looks for a perfect backup band for her Led Zeppelin covers, where a young couple seeks a rabbi for their marriage -- had a premiere for its cast and crew. Craig makes a Hitchcockian cameo in the 80-minute film, with a glimpse of the back of his head. It's fitting. The film isn't really about him, but about the miracles and challenges and intrigue of a full day on his site.

It starts with a voice coming out of the darkness, asking, "Is there really a Craig?"

Craig Newmark started Craigslist in his small circle of friends. Almost 10 years later, the site is one of the Web's top portals, with 5.3 million visitors a month. Craig Newmark isn't the boss at the Craigslist office in San Francisco. That title goes to Jim Buckmaster, right, Craigslist president and CEO.