Redwood City, Calif. -- Turn Inc., a Redwood City-based developer of technology designed to better target online ads, said on Thursday that it has raised $15 million in its third round of funding, led by Palo Alto based Focus Ventures. Norwest Venture Partners, Trident Capital and Shasta Ventures also participated in the round, which increase the company's total backing to $37 million. The company said that it will use the new capital to develop new technology, as well as expand its sales and client services teams. Turn said that its "Smart Market" technology blends and automates multiple ad targeting approaches, then more accurately measures consumers' responses to online ads than most current methods. The company was founded in 2005 by Jim Barnett, the former president of Overture Search and CEO of AltaVista, and John Ellis.