Master's Thesis from the year 2012 in the subject Business economics - Industrial Management, grade: 110/110, University of Siena, course: Industrial economy, language: English, abstract: It has been more than two decades since internet boosted its potential and now it can be considered a fearful competitor of many mortal businesses such as retailers, advertisers or even intermediaries. It is also known that the advent of internet in our daily life has also changed many systems' structures such as the transaction costs in B2B, B2C or even the C2C models. Internet has abolished geographical boundaries, connected people and facilitated information flow. We now live in a world that everything happens in real time, which also brought changes in economic equilibriums, marketing strategies as well as speculation margins. Amazon, Google, EBay has revolutionized the custom of traditional shopping, increasing consumer's addiction to consumption by differentiating products in every possible and imaginable manner. Well, this work's attempt is to shed a light on the dynamics of this evolution, to acknowledge the main players and see how equilibrium can be set and re-set incessantly in a very volatile market due to its lack of physicality (i.e there is a physical gap between supplier and demander at the purchasing moment, therefore is very difficult to build customer loyalty). The example used to extrapolate some statistical evidence is linked to group buying e-commers such as coupon companies. It is the case of Groupon.com, the daily offers company with the highest growth rate among web companies since 2008 . The first part of the study is a theoretical literature review mainly arranged to give a theoretical backup to the empirical analysis that will follow. It seems that there has been a lot of field research on the topic. I suppose the reason is the worryingly fast growing pattern of these virtual business realities. The first chapters aims to concatenate the main features of these new business models, trying to understand the differences between them and the traditional ones which offer the same products or services- also the reasons why 'normal' firms are greatly suffering market share losses. The third chapter instead is totally dedicated to online intermediaries since they seem to be the economic agents to have better fit in this new giant virtual marketplace. Different types of intermediaries obviously play different roles in the business arena and also provoke different welfare effects in terms of costumer's wellbeing. For such reasons the interesting part here is their game strategy while intermediating either information or services.