Social commerce utilizes social media and user contributions to facilitate online buying and selling. It started with social networking sites and f-commerce on Facebook. Retailers recognize the large audiences on sites like Facebook and Twitter and are creating virtual marketplaces and social shopping websites. Benefits for shoppers include informed purchases from reviews and recommendations. Benefits for retailers include targeting large audiences, gaining consumer insights, and increasing sales and profits through word-of-mouth referrals. Some challenges include privacy issues, building customer relationships, and effectively analyzing social media data.