The document discusses the importance of social media marketing. It notes that 1 in 3 media minutes are now spent on mobile devices. There is a symbiotic relationship between customers, media industries, and companies as customers use media for entertainment and information while media industries rely on audiences to sell ads and products to. The document provides examples of how to use major social media platforms like Facebook, Instagram, Twitter, Snapchat and YouTube for marketing purposes. It emphasizes that most potential customers are active on social media, so brands should have a presence across different networks to engage customers and shape online discussions.