The article below describes the ‘positive feedback loop’ that MSFT achieved with Windows, Dev Tools, and Office in th early 90s. MSFT was able to establish a common platform that drove developers to one platform, which in turn drove users to the same platform. Rinse, repeat, and reap.
Facebook is now in a very similar situation, as this post below describes. I couldn’t agree more. The evolution and adoption of new developer technologies in the next 12-24 months will do much to shake out which and how the key web destinations take hold.
Facebook’s move sets them up well–how MSFT, Yahoo, and other SNS sites respond will do much to determine who wins the war.