Interpublic this morning announced a strategic investment in mobile and gaming ad platform Kiip. The investment, which will be overseen by the IPG Media Lab division of Interpublic's Mediabrands, was part of a funding round that raised $11 million for the start-up. Interpublic's stake was not disclosed but it participated in the round at the end of 2012 with Relay Ventures, Hummer Winblad, True Ventures, and Digital Garage.