Until recently, the term Social Media Marketing, was for many marketers unknown. However, during the last couple of years, a new industry of online community tools have shown to have a large impact on the communication between company and consumer. This paper seeks to identify and discuss the main tools of traditional marketing, and thereafter to analyze the difficulty of reaching a set target audience, i.e. the complexity of measuring the effectiveness and Return on Investment. The paper is thereafter introducing the new types of given online marketing tools, such as social networking websites, blogs, microblogs; where users may interact and contribute content among each other, and thereby escape from the ongoing mass communication done by companies. The main advantages such as the ability to effectively analyze a company?s marketing investment, possibility to increase credibility and brand engagement, will be confronted with the question whether this means of online two-way communication is sustainable or not; focusing on the issues of privacy- and message overload.