This doctoral dissertation defines and sheds light on a nascent phenomenon in management, informally referred to as "crowdsourcing". I term this concept Open Source Corporate Strategy, or OSCS, which borrows insights from the open source innovation literature, as well as from the strategy literature. This new concept explains how the firm may incorporate open source principles into its business model, as an effective diversification strategy to gain and sustain competitive advantage, in the context of a globally interconnected society. Firms implementing OSCS make use of a "loose" intellectual property regime to extend their operations outside the formal boundaries of the organization, and orchestrate knowledge work via informal globally distributed communities of practice. Empirical evidence discussed throughout this dissertation shows that these, among others, could be new and important sources of competitive advantage for the firm. Over the last few years we have seen a tremendous increase in the ability of firms to expand operations beyond their boundaries: (1) outside the focal organization, by formally trading knowledge with other organizations external to the firm (Chesbrough 2003, 2006), and more recently, (2) outside the scope of the formal interorganizational fabric, by informally sharing knowledge with external online communities of practice (Lakhani et al., 2007; Villarroel and Tucci 2006). The research developed in this doctoral dissertation was designed to explore this phenomenon, by means of: (1) case studies of firms implementing such open initiatives, (2) computational models of open innovation and open sourcing unveiling their impact on system-level learning performance, complemented by (3) a survey-based study of the online community associated to one such firm-sponsored initiative unveiling the motivation factors that determine participation and contribution performance.