Hivestack , the world’s largest, independent, programmatic digital out of home #AdTECH company has opened up its Ad Server to work with multiple SSP/Exchanges with the introduction of a new, unified auction framework that optimizes publisher yield across various sources. A recent article ‘ Google Still Dominates Advertiser Perceptions SSP Report, But The Field Has Toughened ‘ illustrated that online Web publishers use an average of six SSP/Exchanges for programmatic monetization, with header bidding technology being used to optimize yield.…