Clark is a Los Angeles-based entrepreneur and investor.

Clark is currently executive chairman of Shift, a social media marketing company. Clark was a co-founder of TagWorld, which was sold to Viacom in 2008, and of Top Level Domain Holdings, which is publicly traded on the London AIM. Clark was a founding investor of Adconion and Traffic Marketplace, both leading online advertising networks. Clark is an investor in EdgeCast Networks, Burstly, EcoMom, Scopely, MomentFeed, Cloud Telecomputers, Blacklots, ShopNation, LateNightShots, CityMommy, and LifeCrowd.