1. The document discusses social media marketing (SMM) and group buying sites. SMM involves using social media platforms like forums, blogs, and social networks for marketing. 2. Group buying sites like Groupon and LivingSocial leverage SMM for customer engagement, branding, communications, outreach, feedback, and impulse purchases. They operate by partnering with local businesses to offer discounts that drive sales. 3. Revenue comes from profit-sharing agreements where the group buying site keeps a percentage (usually 40-60%) of sales from each promotional campaign run for a partner business. Areas like customer service, sales, and reporting can potentially be outsourced.