The document discusses Groupon, a coupon website that offers group deals with deep discounts. It provides an overview of Groupon, describing how it was founded in 2008 and achieved rapid growth. The summary also outlines Groupon's business model, explaining that it negotiates deals with local businesses, markets the deals, sells coupons to customers, and charges the businesses a commission. Finally, the summary discusses the advantages and disadvantages of Groupon for businesses, customers, and Groupon itself, and notes how Groupon has developed successfully in Vietnam through effective localization.