Since its birth in 1995, no one knows how much ad revenue Craigslist has cost the newspaper and Yellow Pages industries. This year, however, the free classifieds site will generate $100 million in revenue, according to new data from The AIM Group, parent of consulting group Classified Intelligence -- if that's any indication.

That represents an increase of more than 23% from Craigslist's estimated revenue of $81 million in 2008. Not bad for a site that offers community advertising in some 570 markets worldwide, but which only charges for a tiny percentage of its ads, and at a time when many classified ad publishers are reporting year-over-year revenue declines of more than 50%.

"Craigslist is a stunning business success story, especially since it's run more like a community service than a for-profit business," said Peter Zollman, founding principal of the AIM Group. Also of note, said Zollman, "Craigslist has been having tremendous challenges lately due to negative publicity and legal battles -- but its revenue keeps increasing at a remarkable pace."

The revenue estimate is included in a new Classified Intelligence Report, which attempts to illustrate how Craigslist successfully sidestepped an agreement with state law-enforcement officials about ads for "erotic services."

"Craigslist is often blamed for 'killing newspaper classifieds,' which is an unfair and inaccurate characterization," Zollman said. "It's also been in the news lately because of several killings and literally hundreds of assaults and prostitution arrests that were linked to contacts made on Craigslist.

"Even so, Craigslist is profoundly reshaping the way people connect for jobs, cars, apartments and buying and selling things -- and it keeps growing at a remarkable clip for a company with only about 30 employees and very nominal costs."

The AIM Group began estimating Craigslist's revenue in 2003, when it projected revenue of about $7 million.

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