More quickly than most anyone imagined, blogging is growing up. From the blogosphere's anarchistic roots, a professional cadre is emerging that is creating an industry whose top-performing businesses now earn serious money. The industry is expanding at warp speed. Blog-based media could just be poised to elbow aside traditional print and broadcast outlets to become one of the dominant sources of news, information and opinion, many observers believe.

As blogs mature and start producing good cash flow, they often create additional blogs or new sites, forming networks with multiple products and a common brand identity. For example, GigaOm now offers four additional blogs, all with a common brand, and its staff has grown to 10 full-time employees. "You're seeing small media groups being created," said Paul Walborsky, GigaOm's newly hired chief operating officer. "This is the next evolution."

Such growth has made it easy to raise money. Sequoia Capital, one of Silicon Valley's top venture firms, has contributed almost $10 million in two rounds of financing [in Sugar Inc.]. And NBC's digital media unit, which owns the women-oriented Web site iVillage, invested a little more than $5 million this year, agreed to sell advertising for Sugar sites and is distributing Sugar's content across its properties.