EL SEGUNDO, Calif.--(BUSINESS WIRE)--#ThinkLikeAChallenger--Wpromote takes first-ever outside investment with a new partner in growth, Shamrock Capital. : The Challenger Agency Doubles Down as the Nation’s Largest Independent Digital Agency Alongside New Partner in Growth EL SEGUNDO, Calif.--(BUSINESS WIRE)--Wpromote, the nation’s largest independent digital marketing agency, announced today it has committed to “Make Mondays Suck Less” for a new partner: Shamrock Capital.