Introduction

In the early 1990s, the development of information sharing among individuals on the Internet seemed pervasive. Individuals started to share music files, to communicate word-of-mouth about products and the like. More than ever before a new technology enabled consumers to share information on a large scale and on a spontaneous basis. Most of the attention was then focused on the emergence of online consumers communities (OCCs) and their expected benefits (Wellman and Gulia 1999; Hagel and Armstrong 1997). According to Hagel and Armstrong (1997), OCCs were supposed to offer companies a chance to know their customers much better than ever before, through giving the latter the ability to easily interact with each other and with the company itself: firms organizing OCCs could use what they learned from communities to achieve “viral marketing” and merely create undreamed of customer loyalty.

However, rather little attention had been devoted to identifying potential obstacles to the sustainability of OCCs seen as economic entities providing an informational public good. Yet, shared resources and public goods are shown to give rise to a “tragedy of the commons” (Hardin 1968) since agents' private interest dictates individual behaviors that are eventually harmful to general interest. More precisely, individuals tend to under-invest in a public good because its non-excludability and non-rivalry give private incentives to free-ride, free-riders expecting to benefit from the shared resource even if not contributing to its provision.