This document discusses programmatic advertising ecosystems and real-time bidding (RTB). It describes the various players in the programmatic ecosystem like demand-side platforms, supply-side platforms, ad exchanges, and data providers. It also explains how RTB works through a second-price auction, the pricing models used, and the targeting and buying options available through programmatic advertising. Charts show data on programmatic ad spend trends in Europe and Italy from 2010-2015, with RTB requests growing significantly over that period.