Online ad platform Adify has been sold to Cox Enterprises for $300 million, according to a report in paidContent.org citing unnamed sources. Adify, which is used by Guardian, Forbes.com, NBC WeatherPlus, and Martha Stewart Living Omnimedia, helps other companies develop their own ad networks, paidContent reported.

Investors in the San Bruno, Calif.-based start-up include NBC Universal, US Venture Partners, Venrock Associates, and Time Warner, and has raised $27 million in two rounds of funding. The privately held Cox Enterprises owns Cox Newspapers and Cox Communications, the third-largest cable company in the U.S.

This article is from CNET News.