>Wikipedia improved at a much faster rate, because it had an active community of volunteer contributors who were attracted to its decentralized, community-governed ethos. Does being open contribution warrant the use of the word "decentralised"? as far as I can tell it's still a huge success story from a centralisation perspective.
The website where the efforts were finally consolidated was a central place, but it could very well have been developed as a network of nodes dedicated to different aspects of the explanation of areas of knowledge; the license allowed that. And the growth was initially not coordinated from a central place, an anarchic community began working on different areas and only later began coordinating by building top level behavior policies (as intended).