Craig$list.com

Craig Newmark's stubby fingers tap at the keyboard in an irregular, accelerating rhythm, akin to kernels in a microwave popcorn bag approaching peak heat.

Click-clack.

Click-ity-click-ity-click-ca-
click-clack.

Newmark peers into one of three computer monitors on his home office desk. The screen displays, in plain black-and-white text, the focus of Newmark's daily life -- much of it, anyway. It's in an e-mail program called Pine, favored by geeks of all ages, partly because it renders the mouse nearly useless. Pine users are, like Newmark, the type who derive an almost perverse pleasure from deleting a message by simply pressing the "D" key, rather than undertaking the laborious task of clicking on a trash can icon. Newmark pores over his inbox, which receives about 300 messages daily.

Clack. Clack. Clack. Click-ity-clack-ca-clack.

Every so often, he turns to the left, and his own moving image, collected by a computer video camera, stares back at him from a small laptop screen. Newmark is a young-looking 52, despite his nearly bald pate and stout physique. He wears a deep purple shirt tucked into black pants, fashionable trapezoid-framed glasses, and the perpetual awkward smirk of a middle-aged man who never quite let go of his nerdiness.

There's an e-mail from his nutritionist, who has analyzed data from the pedometer that inhabits Newmark's pocket. "Over the course of two-thirds of the year, I averaged 8,300 steps a day," Newmark says, "but in the last two weeks, I averaged 9,800." His sense of humor is so dry, it's unclear whether he is actually proud of this, and if he is aware that reciting it makes him sound like Rain Man. It's hard to believe this is the Craig Newmark, the Robin Hood of the Internet, who's now sending shock waves through the newspaper industry and becoming a major voice in a movement to reshape the media.

The offices of Craigslist, the mostly free classifieds site Newmark co-founded a decade ago, are less than a mile to the west, but he spends most of his workweek here, at the Inner Sunset house his girlfriend teasingly calls his "swank new bachelor pad." Newmark moved in in October, and his progress does much to reveal his priorities: The wall that will separate the bedroom from the bathroom has yet to be built, but two brand-new, widescreen televisions (one in the living room, one at the foot of the bed) are fully functional.

Newmark lightly rubs his index finger over the pink keyboard nub that programmers call the "nipple mouse." The arrow on the screen dashes from the left monitor to the right. A Web page shows Newmark the ads that have been "flagged" -- some users thought the posts were spam, fraud schemes, or other misbehavior. In the forums, where Craigslist community members debate and commiserate in an online free-for-all, Newmark acts as benevolent dictator -- the editor in chief, as it were, of Craigslist.org. He decides who's suspended, who's deleted, and who is relegated to the "Island of Misfit Threads" with a single click.

"This guy's a bigot," he says, pointing to a post that reads "my boss is a jew." Newmark adds: "I've seen him before.

"He's gone." Clack! "This guy is troubled, just a nasty piece of work. He's welcome as long as he behaves like an adult," Newmark says, in his best imitation of a junior high principal. "I've spoken about it with him ...." He trails off, moving to the next flag, which alerts him to a group spamming the erotic services section. Newmark blocks them from posting by clicking a button that reads "Sweep the Leg!," a jokey reference to an illegal kick by one of the bad guys in The Karate Kid. Two other Craigslist employees monitor the posts, but there's no simple way to pass on the knowledge Newmark has gained fighting spam, essentially by hand, for almost 10 years.

This is how the multimillion-dollar global corporation that is Craigslist Inc. remains operational: with the founder sitting at home for hours a day, pointing and clicking on a "Sweep the Leg!" button. Yet the consequences of this bare-bones behemoth's rise now stretch far beyond Newmark's home and the Craigslist community.

Almost by accident, Newmark built one of the Internet's most successful sites, creating a free marketplace for millions that continues to grow around the country and the world. Among the unintended consequences of Craigslist's growth, though, is that it's sucking away significant dollars in classified advertisements from already-struggling newspapers. Bay Area papers alone forfeit at least $50 million annually to Craigslist, losses that contribute to layoffs of dozens of reporters. As fearful publishers cut newsroom jobs, inferior news coverage is the likely outcome. Craigslist's devoted fans are unknowingly exchanging one public service for another -- trading away the quality of their news for a cheaper way to find an apartment. At the same time, Craigslist's executives won't disclose the amount of money they're pulling in.