Inc Biz NetAfter losing out on a bid to acquire—and save—Business 2.0, it appears Joe Mansueto is launching a real business 2.0 of his own. Mansueto Digital, the online arm of the Inc. and Fast Company publisher, has launched IncBizNet, a social networking site targeted at private U.S. businesses.

The site “will become an extensive directory of U.S.-based private companies” with profile data regularly provided and updated by the companies themselves, including a press release newswire, blogs and community groups for entrepreneurs.

“We expect the directory of companies on will become the most detailed, accurate database of private company information in the United States,” Mansueto Digital VP Ed Sussman said in a statement announcing the launch.

IncBizNet is the first product to be rolled out from the $10 million investment Mansueto made in the digital division earlier this year

“IncBizNet will greatly enhance the capacity of our company to offer compelling sponsorship platforms to our advertisers,” said Mansueto Ventures CEO John Koten. “It will also enhance our ability find great companies with great stories for our journalists to cover, making our magazine, websites, and events even more compelling.”

American Express Open and Comcast will serve as the site’s launch sponsors.

The site will be pre-populated with companies from this year’s Inc. 5,000 list of the fastest-growing privately held companies in the U.S., with “more than a dozen” staffers working on company outreach for Mansueto Digital.

IncBizNet’s lofty goal? A million participating private companies.