Instagram has over 130 million active users who share over 40 million photos per day. Millennials are especially active on Instagram, with 28% of US internet users aged 18-29 using the platform. Many brands are increasingly using Instagram to engage with customers, with 41% of brands posting at least once a week. The presenter discusses how the San Francisco Giants and other companies like Starbucks, Red Bull, and Nike leverage Instagram for marketing through contests, sponsored content, and allowing fans to showcase the brand.