Creating viral videos and concepts has become a keystone for many businesses marketing online.

Such Web phenomena are known by technophiles as "memes." Coined by biologist Richard Dawkins in his 1976 book "The Selfish Gene," a meme is a unit of cultural information -- an idea, a practice, a phrase, or an online video --that's passed on virally. Although sometimes frivolous, every word-of-mouth marketer dreams of creating memorable memes that will catapult their product or client to fame.

Over the last few years, 4chan.org has become one of the most talked-about sites when it comes to launching new memes. After appearing on the site, "LOLcats," humorous images of cats with loud text beneath them in a fake language called "LOLspeak", stormed the Web last year. (For example, instead of saying "hello," the cats would say "oh hai.") Another phrase "So I herd u like mudkips," a reference to a sea creature from the popular animated show "Pokémon," spawned thousands of tribute videos on YouTube. 4chan.org began as a simple message board with pictures and text. It was started by Christopher Poole in his Long Island bedroom in 2003 when he was 15 years old. Since then it has grown to more than 3 million monthly users, according to Mr. Poole.

One of the site's most popular memes is an online bait-and-switch known as the "Rick Roll." Here's how it works: A friend sends an email suggesting you take a peek at an "amazing" online video and passes along the link. You follow the link, but instead of the video you expect, you've been sent to the music video of Rick Astley's "Never Gonna Give You Up," a hit song from 1988. Over the past year, Rick Rolling has become an online sensation, pushing Mr. Astley's video past 16 million views on YouTube.

4chan is a quaint throwback to the earliest Web pages that have since been eclipsed in the newest iterations of the Web. While other Web sites focus on flashy-social networking features and eye-catching advertisements, 4chan's design is archaic and the color scheme is two-tone. Each page on 4chan features photos and text. One user will post an image of something to start a discussion on one of the more than 40 different subject areas spanning origami and automobiles. Other users follow up with responses or requests for more images.

"It's like Craigslist -- hugely simple and highly useful," says David Weinberger, a fellow at Harvard University's Berkman Center for Internet and Society. 4chan's utility is its ability to gather millions of people in conversation in a single place and create a "meme-rich" environment, says Mr. Weinberger.

Last September, Ben Huh and a team of investors purchased "I Can Has Cheezburger," a site that aggregated the "LOLcats." Mr. Huh hopes to turn the 4chan-generated tradition into a meme empire with several other related sites in the works. The site now has more than 2.5 million unique visitors a month, according to Mr. Huh, and a book based on the site is coming this fall for Gotham Books.

Mr. Poole originally just wanted a place to share his fascination with Japanese comics and television shows. He was a fan of the popular Japanese image Web site 2chan and wanted to create a version for American audiences. With his mother's approval, he used her credit card to purchase server space and started 4chan.org.

oon, running 4chan became a full-time job. He hired a programmer (based on his skill playing online Tetris) and recruited a team of active community members to serve as moderators. "It was a struggle to get him to turn off his computer," says Tom Poole, Mr. Poole's father, who says his son built a computer with a water-cooling system as a teen. "He's a bit obsessive."

A large part of the site's success is its emphasis on anonymity. Users are not required to provide a working email address or any other personal information, a standard practice for other online communities like Facebook or MySpace. Mr. Poole uses the codename "moot" and says that he's never revealed his connection to the site until The Wall Street Journal inquired. "I have a firewall between my two lives," he says.

Mr. Poole says that anonymity encourages unfettered creativity. But it also removes individual accountability as some posts can veer into hurtful or profane territories. "Shock posts," or graphic images of violence or sex, occasionally mar the largest general interest board known as " /b/ ." Mr. Poole has a disclaimer that he wrote so that users "don't post anything that violates U.S. or international law." He says a lawyer reviewed the notice, but concedes, "I'm sure they don't have much legal clout behind them."

"They get rowdy -- it's like a bar without alcohol," says Willard Ling, a moderator and long-time user of the site. "It's like that psychological concept of deinvidualization -- when groups of people become less aware of their own responsibility." Mr. Poole and his team of moderators have handed out 70,000 bans over the last three years, but preventing long-term abuse can be difficult.

4chan's "Wild West" reputation has created a dilemma for Mr. Poole. While it's brought him Internet fame, albeit through his alter ego, and created enviable traffic, he has trouble selling ads to more cautious companies who don't want their ads appearing next to potentially graphic content. He's attempted to quarantine sexual material on a set of adult boards, but that doesn't stop pornography or other adult content from appearing elsewhere.

Max Goldberg, owner of You're The Man Now Dog, a similar community with about 230,000 registered users and a focus on animated videos, says dealing with mature content is a problem for any site that allows its users creative license. "On the Web, you either have clean content or you have pornography. People upload both, but they don't want to buy pornography, because they can get it for free," says Mr. Goldberg. Even a small percentage of racy or blue content can ruin a site's image with advertisers, he says.

4chan's growing pains are part of a larger issue: how to turn a wave of online traffic into a viable business. "That's been an uphill battle for me personally. My biggest time spent has been convincing companies in marketing potential in 4chan but no one sees eye to eye," says Mr. Poole.

Part of 4chan's problem is counting how many users are on the site. Many advertisers look at third-party Web-measurement companies like comScore to determine a site's overall traffic and demographic information. Currently, comScore says 4chan only has around about 796,000 unique visitors a month globally, a more than threefold difference from 4chan's claims. ComScore says that it uses a Nielsen-like system to track Web traffic.

Mr. Poole says that comScore's demographic data is correct, but disagrees with their traffic data, arguing that panel-based data is flawed. "It's a generalization," he says of comScore's figures, "Our users are hard to pinpoint."

In contrast to other startups that have amassed millions of dollars in seed money from investors, 4chan is a modest operation. Mr. Poole makes money from advertising and the occasional donation drive. He says the site breaks even, but won't release the site's revenue figures. His only paid staff member is his programmer. "He makes more money than I do," says Mr. Poole.

It's like Craigslist -- hugely simple and highly useful