Fortuny spent most of the weekend in his bedroom juggling several windows on his monitor. One displayed a chat room run by Encyclopedia Dramatica, an online compendium of troll humor and troll lore. It was buzzing with news of an attack against the Epilepsy Foundation's Web site. Trolls had flooded the site's forums with flashing images and links to animated color fields, leading at least one photosensitive user to claim that she had a seizure.

WEEV: the whole posting flashing images to epileptics thing? over the line.

HEPKITTEN: can someone plz tell me how doing something the admins intentionally left enabled is hacking?

WEEV: it's hacking peoples unpatched brains. we have to draw a moral line somewhere.

Fortuny disagreed. In his mind, subjecting epileptic users to flashing lights was justified. "Hacks like this tell you to watch out by hitting you with a baseball bat," he told me. "Demonstrating these kinds of exploits is usually the only way to get them fixed."

"So the message is 'buy a helmet,' and the medium is a bat to the head?" I asked.

"No, it's like a pitcher telling a batter to put on his helmet by beaning him from the mound. If you have this disease and you're on the Internet, you need to take precautions." A few days later, he wrote and posted a guide to safe Web surfing for epileptics.

On Sunday, Fortuny showed me an office building that once housed Google programmers, and a low-slung modernist structure where programmers wrote Halo 3, the best selling video game. We ate muffins at Terra Bite, a coffee shop founded by a Google employee where customers pay whatever price they feel like. Kirkland seemed to pulse with the easy money and optimism of the Internet, unaware of the machinations of the troll on the hill.

We walked on, to Starbucks. At the next table, middle schoolers with punk rock haircuts feasted noisily on energy drinks and whipped cream. Fortuny sipped a white chocolate mocha. He proceeded to demonstrate his personal cure for trolling, the Theory of the Green Hair.

"You have green hair," he told me. "Did you know that?"

"No," I said.

"Why not?"

"I look in the mirror. I see my hair is black."

"That's uh, interesting. I guess you understand that you have green hair about as well as you understand that you're a terrible reporter."

"What do you mean? What did I do?"

"That's a very interesting reaction," Fortuny said. "Why didn't you get so defensive when I said you had green hair?" If I were certain that I wasn't a terrible reporter, he explained, I would have laughed the suggestion off just as easily. The willingness of trolling "victims" to be hurt by words, he argued, makes them complicit, and trolling will end as soon as we all get over it.

*****

On Monday we drove to the mall. I asked Fortuny how he could troll me if he so chose. He took out his cellphone. On the screen was a picture of my debit card with the numbers clearly legible. I had left it in plain view beside my laptop. "I took this while you were out," he said. He pressed a button. The picture disappeared. "See? I just deleted it."

The Craigslist Experiment, Fortuny reiterated, brought him troll fame by accident. He was pleased with how the Megan Had It Coming blog succeeded by design. As he described the intricacies of his plan - adding sympathetic touches to the fake classmate, making fake Lori Drew a fierce defender of her own daughter, calibrating every detail to the emotional register of his audience - he sounded not so much a sociologist as a playwright workshopping a set of characters.

"You seem to know exactly how much you can get away with, and you troll right up to that line," I said. "Is there anything that can be done on the Internet that shouldn't be done?"

Fortuny was silent. In four days of conversation, this was the first time he did not have an answer ready.

"I don't know," he said. "I have to think about it."

Sherrod DeGrippo, a 28-year-old Atlanta native who goes by the name Girlvinyl, runs Encyclopedia Dramatica, the online troll archive. In 2006, DeGrippo received an e-mail message from a well known band of trolls, demanding that she edit the entry about them on the Encyclopedia Dramatica site. She refused. Within hours, the aggrieved trolls hit the phones, bombarding her apartment with taxis, pizzas, escorts and threats of rape and violent death. DeGrippo, alone and terrified, sought counsel from a powerful friend. She called Weev.

Weev, the troll who thought hacking the epilepsy site was immoral, is legendary among trolls. He is said to have jammed the cellphones of daughters of CEO's and demanded ransom from their fathers; he is also said to have trashed his enemies' credit ratings. Better documented are his repeated assaults on LiveJournal, an online diary site where he himself maintains a personal blog. Working with a group of fellow hackers and trolls, he once obtained access to thousands of user accounts.

I first met Weev in an online chat room that I visited while staying at Fortuny's house. "I hack, I ruin, I make piles of money," he boasted. "I make people afraid for their lives." On the phone that night, Weev displayed a misanthropy far harsher than Fortuny's. "Trolling is basically Internet eugenics," he said, his voice pitching up like a jet engine on the runway. "I want everyone off the Internet. Bloggers are filth. They need to be destroyed. Blogging gives the illusion of participation to a bunch of retards. . . . We need to put these people in the oven!"

I listened for a few more minutes as Weev held forth on the Federal Reserve and about Jews. Unlike Fortuny, he made no attempt to reconcile his trolling with conventional social norms. Two days later, I flew to Los Angeles and met Weev at a train station in Fullerton, a sleepy bungalow town folded into the vast Orange County grid. He is in his early 20s with full lips, darting eyes and a nest of hair falling back from his temples. He has a way of leaning in as he makes a point, inviting you to share what might or might not be a joke.

As we walked through Fullerton's downtown, Weev told me about his day - he'd lost $10,000 on the commodities market, he claimed - and summarized his philosophy of "global ruin." "We are headed for a Malthusian crisis," he said, with professorial confidence. "Plankton levels are dropping. Bees are dying. There are tortilla riots in Mexico, the highest wheat prices in 30-odd years." He paused. "The question we have to answer is: How do we kill four of the world's six billion people in the most just way possible?" He seemed excited to have said this aloud.

*****

Ideas like these bring trouble. Almost a year ago, while in the midst of an LSD-and-methamphetamine bender, a longer-haired, wilder-eyed Weev gave a talk called "Internet Crime" at a San Diego hacker convention. He expounded on diverse topics like hacking the Firefox browser, online trade in illegal weaponry and assassination markets - untraceable online betting pools that pay whoever predicts the exact date of a political leader's demise. The talk led to two uncomfortable interviews with federal agents and the decision to shed his legal identity altogether. Weev now espouses "the ruin lifestyle" - moving from condo to condo, living out of three bags, no name, no possessions, all assets held offshore. As a member of a group of hackers called "the organization," which, he says, bring in upward of $10 million annually, he says he can wreak ruin from anywhere.

We arrived at a strip mall. Out of the darkness, the coffinlike snout of a new Rolls Royce Phantom materialized. A flying lady winked on the hood. "Your bag, sir?" said the driver, a blond kid in a suit and tie.

"This is my car," Weev said. "Get in."

And it was, for that night and the next, at least. The car's plush chamber accentuated the boyishness of Weev, who wore sneakers and jeans and hung from a leather strap like a subway rider. In the front seat sat Claudia, a pretty college age girl.

I asked about the status of Weev's campaign against humanity. Things seemed rather stable, I said, even with all this talk of trolling and hacking.

"We're waiting," Weev said. "We need someone to show us the way. The messiah."

"How do you know it's not you?" I asked.

"If it were me, I would know," he said. "I would receive a sign."

Zeno of Elea, Socrates and Jesus, Weev said, are his all-time favorite trolls. He also identifies with Coyote and Loki, the trickster gods, and especially with Kali, the Hindu goddess of destruction. "Loki was a hacker. The other gods feared him, but they needed his tools."

"I was just thinking of Kali!" Claudia said with a giggle.

Over a candlelit dinner of tuna sashimi, Weev asked if I would attribute his comments to Memphis Two, the handle he used to troll Kathy Sierra, a blogger. Inspired by her touchy response to online commenters, Weev said he "dropped docs" on Sierra, posting a fabricated narrative of her career alongside her real Social Security number and address. This was part of a larger trolling campaign against Sierra, one that culminated in death threats. Weev says he has access to hundreds of thousands of Social Security numbers. About a month later, he sent me mine.

Weev, Claudia and I hung out in Fullerton for two more nights, always meeting and saying goodbye at the train station. I met their friend Kate, who has been repeatedly banned from playing XBox Live for racist slurs, which she also enjoys screaming at white pedestrians. Kate checked my head for lice and kept calling me "Jew." Relations have since warmed. She now e-mails me puppy pictures and wants the names of fun places for her coming visit to New York. On the last night, Weev offered to take me to his apartment if I wore a blindfold and left my cellphone behind. I was in, but Claudia vetoed the idea. I think it was her apartment.

Does free speech tend to move toward the truth or away from it? When does it evolve into a better collective understanding? When does it collapse into the Babel of trolling, the pointless and eristic game of talking the other guy into crying "uncle"? Is the effort to control what’s said always a form of censorship, or might certain rules be compatible with our notions of free speech?

One promising answer comes from the computer scientist Jon Postel, now known as "god of the Internet" for the influence he exercised over the emerging network. In 1981, he formulated what's known as Postel's Law: "Be conservative in what you do; be liberal in what you accept from others." Originally intended to foster "interoperability," the ability of multiple computer systems to understand one another, Postel's Law is now recognized as having wider applications. To build a robust global network with no central authority, engineers were encouraged to write code that could "speak" as clearly as possible yet "listen" to the widest possible range of other speakers, including those who do not conform perfectly to the rules of the road. The human equivalent of this robustness is a combination of eloquence and tolerance - the spirit of good conversation. Trolls embody the opposite principle. They are liberal in what they do and conservative in what they construe as acceptable behavior from others. You, the troll says, are not worthy of my understanding; I, therefore, will do everything I can to confound you.

Why inflict anguish on a helpless stranger? It's tempting to blame technology, which increases the range of our communications while dehumanizing the recipients. Cases like An Hero and Megan Meier presumably wouldn't happen if the perpetrators had to deliver their messages in person. But while technology reduces the social barriers that keep us from bedeviling strangers, it does not explain the initial trolling impulse. This seems to spring from something ugly - a destructive human urge that many feel but few act upon, the ambient misanthropy that's a frequent ingredient of art, politics and, most of all, jokes. There’s a lot of hate out there, and a lot to hate as well.

So far, despite all this discord, the Internet's system of civil machines has proved more resilient than anyone imagined. As early as 1994, the head of the Internet Society warned that spam "will destroy the network." The news media continually present the online world as a Wild West infested with villainous hackers, spammers and pedophiles. And yet the Internet is doing very well for a frontier town on the brink of anarchy. Its traffic is expected to quadruple by 2012. To say that trolls pose a threat to the Internet at this point is like saying that crows pose a threat to farming.

That the Internet is now capacious enough to host an entire subculture of users who enjoy undermining its founding values is yet another symptom of its phenomenal success. It may not be a bad thing that the least mature users have built remote ghettos of anonymity where the malice is usually intramural. But how do we deal with cases like An Hero, epilepsy hacks and the possibility of real harm being inflicted on strangers?

Several state legislators have recently proposed cyberbullying measures. At the federal level, Representative Linda Sanchez, a Democrat from California, has introduced the Megan Meier Cyberbullying Prevention Act, which would make it a federal crime to send any communications with intent to cause "substantial emotional distress." In June, Lori Drew pleaded not guilty to charges that she violated federal fraud laws by creating a false identity "to torment, harass, humiliate and embarrass" another user, and by violating MySpace's terms of service. But hardly anyone bothers to read terms of service, and millions create false identities. "While Drew's conduct is immoral, it is a very big stretch to call it illegal," wrote the online-privacy expert Prof. Daniel J. Solove on the blog Concurring Opinions.

Many trolling practices, like prank calling the Hendersons and intimidating Kathy Sierra, violate existing laws against harassment and threats. The difficulty is tracking down the perpetrators. In order to prosecute, investigators must subpoena sites and Internet service providers to learn the original author's IP address, and from there, his legal identity. Local police departments generally don't have the means to follow this digital trail, and federal investigators have their hands full with spam, terrorism, fraud and child pornography. But even if we had the resources to aggressively prosecute trolls, would we want to? Are we ready for an Internet where law enforcement keeps watch over every vituperative blog and backbiting comments section, ready to spring at the first hint of violence? Probably not. All vigorous debates shade into trolling at the perimeter; it is next to impossible to excise the trolling without snuffing out the debate.

If we can't prosecute the trolling out of online anonymity, might there be some way to mitigate it with technology? One solution that has proved effective is "disemvoweling" - having message-board administrators remove the vowels from trollish comments, which gives trolls the visibility they crave while muddying their message. A broader answer is persistent pseudonymity, a system of nicknames that stay the same across multiple sites. This could reduce anonymity's excesses while preserving its benefits for whistle-blowers and overseas dissenters. Ultimately, as Fortuny suggests, trolling will stop only when its audience stops taking trolls seriously. "People know to be deeply skeptical of what they read on the front of a supermarket tabloid," says Dan Gillmor, who directs the Center for Citizen Media. "It should be even more so with anonymous comments. They shouldn't start off with a credibility rating of, say, 0. It should be more like negative 30."

Of course, none of these methods will be fail-safe as long as individuals like Fortuny construe human welfare the way they do. As we discussed the epilepsy hack, I asked Fortuny whether a person is obliged to give food to a starving stranger. No, Fortuny argued; no one is entitled to our sympathy or empathy. We can choose to give or withhold them as we see fit. "I can't push you into the fire," he explained, "but I can look at you while you're burning in the fire and not be required to help." Weeks later, after talking to his friend Zach, Fortuny began considering the deeper emotional forces that drove him to troll. The theory of the green hair, he said, "allows me to find people who do stupid things and turn them around. Zach asked if I thought I could turn my parents around. I almost broke down. The idea of them learning from their mistakes and becoming people that I could actually be proud of ... it was overwhelming." He continued: "It's not that I do this because I hate them. I do this because I'm trying to save them."

Weeks before my visit with Fortuny, I had lunch with "moot," the young man who founded 4chan. After running the site under his pseudonym for five years, he recently revealed his legal name to be Christopher Poole. At lunch, Poole was quick to distance himself from the excesses of /b/. "Ultimately the power lies in the community to dictate its own standards," he said. "All we do is provide a general framework." He was optimistic about Robot9000, a new 4chan board with a combination of human and machine moderation. Users who make "unoriginal" or "low content" posts are banned from Robot9000 for periods that lengthen with each offense.

The posts on Robot9000 one morning were indeed far more substantive than /b/. With the cyborg moderation system silencing the trolls, 4chan had begun to display signs of linearity, coherence, a sense of collective enterprise. It was, in other words, robust. The anonymous hordes swapped lists of albums and novels; some had pretty good taste. Somebody tried to start a chess game: "I'll start, e2 to e4," which quickly devolved into riffage with moves like "Return to Sender," "From Here to Infinity," "Death to America" and a predictably indecent checkmate maneuver.

Shortly after 8 a.m., someone asked this:

"What makes a bad person? Or a good person? How do you know if you're a bad person?"

Which prompted this:

"A good person is someone who follows the rules. A bad person is someone who doesn't."

And this:

"you're breaking my rules, you bad person"

There were echoes of antiquity:

"good: pleasure; bad: pain"

"There is no morality. Only the right of the superior to rule over the inferior."

And flirtations with postmodernity:

"good and bad are subjective"

"we're going to turn into wormchow before the rest of the universe even notices."

Books were prescribed:

"read Kant, JS Mill, Bentham, Singer, etc. Noobs."

And then finally this:

"I'd say empathy is probably a factor."