The presence of companies and brands in social networks becomes critical for effectively promoting any product or service and gain customer loyalty. The new role of Internet users as active consumers while generating content (prosumers), has completely revolutionized the traditional marketing strategies and business communication with customers. Social networks are places where users recommend their favorite products and services, but also where they share and potentially harmful negative opinions about anything that disappoints them. Therefore, 2.0. platforms are the vital new scope for any business that wants to succeed in an ever-changing environment. Besides being a powerful communication channels with your clients, social networks can create community and loyalty around a brand at a very low economic costs. The marketing applied to social networks will enhance the expansion of any business in the digital economy. This book covers all these topics in depth.