Of all the recent trends in online computing, the one most game-changing is the trend toward developing platforms and allowing users to build applications on top of them. The greatest example of a platform on the web is Facebook, which started as a simple social network, but by opening up to third party apps, has become the most important web development since Google. Platforms allow downstream developers to wield the entire power of the “parent” to create interesting and valuable applications without requiring massive resources to lay the groundwork for the basic functionality.
The reason platforms are so important is that they allow developers to use massive technological leverage. To illustrate this point, lets use the example of Dropbox, an outstanding online backup application.