When Google first announced Knol, the search giant's high-minded answer to Wikipedia, few thought the service would take off. But now, less than a month after its launch, the new service has brought back the old fears of many media companies and publishers.

For years, Google has walked a fine line between its stated role as a search engine and a content company, but Knol, which allows users to post ad-supported articles on any topic, has many worried that Google is in fact becoming a content provider.

"If in fact a Google property is taking money away from Google's partners, that is a real problem," Wenda Harris Millard, the co-chief executive of Martha Stewart Living Omnimedia told The New York Times.

Millard's concern is that as Knol gains in popularity, its pages may beat out other publishers for popular searches. While she says she doesn't believe that Google is favoring its Knol pages, she is worried that the search giant has a rather obvious conflict of interest if it makes money by both locating and selling content.

For now, there are only a handful of Knol pages. But if more users start publishing on Knol, it won't take long for the Google product to usurp at least some of Wikipedia's power. And if that happens, there's likely to be a reordering of the search universe, with Google dominating both the process and the results.