It’s not just a hobby — some small sites are making big money. Here’s how to turn your passion into an online empire.

Journalist Mark Frauenfelder founded Boing Boing, then a paper-based cyberpunk zine, in 1988 and took it online in 1995. Four years later he accepted a freelance assignment to write what became one of the first stories about blogs–and afterward decided to turn his zine into one. He discovered the power of building traffic by “deep linking” to specific stories or items on other sites. Other bloggers would return the favor, and the community grew. “I was getting a thousand visitors a day, and I thought, ‘Oh, that’s fun,’” Frauenfelder recalls.

Eventually he discovered that the more posts Boing Boing put up, the more traffic grew; he recruited three friends to keep the posts coming hot and heavy. By 2004 the site had 20,000 visitors a day, rivaling many mainstream magazine sites. But the team was spending about a thousand bucks a month in Web hosting fees. That’s when Frauenfelder called Battelle, a former colleague, and began selling ads for the site. Today, Boing Boing’s roughly 325,000 daily visitors make it the most lucrative property in Battelle’s stable. Though not all of Boing Boing’s ad inventory is sold, the site will gross more than $1 million this year, based on CPMs and traffic. “It’s turned out to be a good business,” Frauenfelder says.

But Battelle believes an eccentric blog called Fark.com, a collection of reader-submitted links to amusing videos, jokes, and curiosities from all over the Web, could become the most profitable site in mainstream blogdom. Already it vies with FM stablemate MetaFilter for the top spot in blog traffic rankings. Fark founder Drew Curtis made up the site’s offbeat name as code for the real F-word when posting in chat rooms in the early 1990s. In 1993, while a student in England, Curtis began sending e-mail messages to friends back home with weird items he found in the news. In 1999 he decided to post them on a webpage. Fark is incredibly cost-efficient: Almost all of its content is generated by its readers, and aside from Curtis it has just two contract employees, both tech guys. Fark devotees post links to news items accompanied by rubrics like “spiffy” and “dumbass,” annotate them with blurbs of text, and open them up for comment. Controversial items about politics, religion, or sex ignite all-out flame wars–and, naturally, boost traffic, which overall stands at 40 million pageviews a month. The beautiful part is that virtually none of the content (pictures, videos, etc.) is hosted on Fark, which simply links to the goodies. This means that, despite its huge traffic, Fark doesn’t incur the crushing bandwidth fees that eat into profit at sites like video trove YouTube.