The document discusses the concept of digital and how it has changed marketing. It notes that digital is a network of networks or a pool of human knowledge and culture that allows for new forms of learning, broadcasting, commerce, communication, social connection, publishing, entertainment, staying up to date, gathering opinions, sharing, and self expression. It also discusses how digital has changed roles for creative agencies, content owners, media buyers, and consumers. Brands are now under more consumer control and digital provides opportunities for consumer endorsement and two-sided conversations. The challenges are ensuring brands can be found, listen, create, interact and treat digital like other products by understanding users and measuring impact.