First let's consider the underlying models and theories. In 1967 Stanley Milgram of Harvard University investigated, within the framework of the "small world experiment," the average number of interstations that separated two randomly selected persons (X, Y) within a social network. The resulting number was surprisingly low: Six. The famous "six degrees of separation" was born. At one stroke the world had become flatter.

Three years later, in 1970, Mark Granovetter from Johns Hopkins University discovered that for finding a new job what you knew mattered less than whom you knew. And not only that - how you knew them was also important. Interestingly, it wasn't close friends but rather acquaintances one met occasionally who were the most reliable sources of new jobs. "The Strength of Weak Ties" (Granovetter, 1973) and the utility of a large, loose-knit network beyond one´s circle of friends had been proven. Growing international interconnectedness bestowed a decisive competitive advantage on those who successfully fostered those weak ties. Appropriately, the 70s was also the decade in which email was invented.

In 1988 James Coleman of the University of Chicago merged all resources inherent in social relations into the concept of social capital. Humans, he found, used their relations like physical or financial capital to achieve their objectives. Anyone could transform one form of capital into another. Still in its infancy, the Internet could not yet provide the adequate technology. However, little more than 10 years later, the social-capital concept along with the aforementioned findings became decisive incentives for the development of platforms like MySpace, LinkedIn, and Facebook.