The documents describe the digital media and programmatic advertising ecosystems. The digital media landscape includes various types of digital ads like display, video, mobile, and native ads. The advertising business is transforming due to factors like the rise of influencer marketing, concentration of ad spending among large tech companies, use of audience data and AI for targeting, and automation of the buying and selling process. The programmatic ecosystem involves various players like brands, publishers, agencies, ad exchanges, demand side platforms, and supply side platforms that facilitate the automated sale of digital ads through real-time bidding.