Los Angeles-based SodaHead has tapped a digital advertising and marketing agency to represent its inventory on a real time bidding platform. According to engage:BDR, which operates the First Impression real-time bidding platform, SodaHead is adding its more than 10 million monthly unique visitors to its platform. engage:BDR said that SodaHead's largest demographic is in the 18-24 range. engage:BDR says it has a reach of 109 million monthly unique users. SodaHead operates an online site focused on discussions, opinions, and polls.