One of the best-performing technologies in online advertising right now is retargeting—everyone from Google to startups are making bank from it. That's when you browse the Web and are shown an ad from a site you've visited in the past. The clickthroughs are much higher than a random display ad. Now, a New York City startup called Tapad is bringing retargeting to mobile devices. Tapad was founded by Are Traasdahl, who previously was the founder and CEO of mobile entertainment company Thumbplay . He's raised $1.8 million from Metamorphic Ventures, Firstmark Capital, Lerer Ventures, and a Who's Who of ad tech angel investors, including former DoubleClick CEO David Rosenblatt, Clickable CEO David Kidder, 24/7 Real Media co-founder Geoff Judge, AppNexus founder (and former Right Media CTO) Brian O'Kelly, Tacoda founder Dave Morgan, OpenX founder Scott Switzer, Hashable (and former Quigo) CEO Michael Yavonditte, and SecondMarket CEO Barry Silbert. Yeah, that's a hell of a list of entrepreneurs who created some of the most valuable online advertising companies of the last decade.