Optimal, a media buying platform for social advertising, has raised $7 million in Series B venture funding from DoubleRock, The Social Internet Fund, Siemer Ventures, Signal Ventures, John Pappajohn, Warren Adelman, Social Starts, James Altucher and Silicon Valley Bank. Series A investors Neu Ventures, Stonnington Asset Allocation Fund, and WGI Group participated.[Source: Optimal]