This paper intends to illustrate and make more explicit the decentralization argument put forward in the literature on platform leadership. The analysis shows that in the digital economy, where rapid scalability and evolvability are so important, decentralization has played a crucial role in the success of some open platforms, as against the failure of other, also open but more centralized, platforms. More specifically, on the basis of four comparative case studies, the paper shows that platform leaders should beware of offering the market too heavy a platform core, lest the platform's neutrality, scalability and evolvability be compromised. r