The document provides examples of how various brands have successfully used social media to engage customers and increase sales and brand awareness. It describes campaigns by American Express, Coca-Cola, Sauza Tequila, Rom chocolate, Omo detergent, Tesco, Wonga, Dos Equis and PayPal that utilized tactics like viral videos, custom products, online stores and conversations to build communities and drive increases in metrics like sales, website traffic, fan growth and brand consideration. The key takeaways emphasize using social media as part of an overall brand strategy to build relationships and engage customers through shared value.