For some time now, online communities are receiving the attention of companies and researchers for their value creation potential for both consumers and firms. Recognizing the importance of online communities for business, both practitioners and business researchers have written much about it in the last fifteen years. However, despite the profusion of literature on the subject, there is a notorious lack of one piece of work that extensively explain all the processes companies can undertake in order to create value with consumers through online communities. Thus, in its first phase, this dissertation attempts to fulfill this need through a general qualitative approach which systematizes a vast amount of primary and secondary data, giving rise to a taxonomy. As ‘online community’ is a wide concept whose definition is far from consensus, we start by adopting mid-range work definition: a group of people with a common or complementary goal or interest, who join in a common virtual space with potential to support social exchange, following a given set of rules. The study enabled the identification and exhaustive characterization of four major strategies that companies may adopt in order to create value with consumers through online communities: (1) Creating OC-based business models; (2) Creating OCs as supplement of a core business; (3) Establishing close relationships with consumer-run OCs; (4)Using the services from other companies’ revenue-generating OCs.Throughout the development of this first phase of the dissertation, a new and consequently understudied phenomenon in the field of consumer online communities was identified and named Company Social Network (CSN). The remaining dissertation work is thus entirely devoted to this new phenomenon defined as a group of people (followers, fans, or some other term, according to the website terminology) connected to a company or brand within the boundaries of a social networking site. A mixed method approach, in which a qualitative study is followed by a quantitative study, is used to study the antecedents and consequences of participation in CSNs. In the first study, by interviewing members, it was possible to identify the drivers of participation in CSNs, which proved to be somehow similar to the factors identified in already studied online and brand communities, however, differently from what happens in those communities, more oriented towards the host company than to the other CSN members. In the second study, based on the results of the first, along with literature review, a conceptual model was built with the aims of assessing: how different factors have impact in the attitudes (satisfaction and identification with the CSN) and participation behaviors (loyalty) of members towards the CSN as well as (2) how attitude and behavior towards CSN influences satisfaction and loyalty to the host-company. The results of this study confirmed that all the previously identified factors really drive loyalty to the CSN. The study also showed that those factors may be divided into factors of satisfaction with the CSN and factors of identification with the CSN, which are different paths to loyalty. Factors of satisfaction are mainly functional and factors of identification are predominantly social. Although the study indicated that only satisfaction with the CSN (and not identification) has a direct impact on satisfaction with the host-company, it also suggested that companies should not disregard any factor. Identification has the potential to improve the levels of engagement with the CSN, increasing the opportunities of value cocreation.