If a platform achieves scale and becomes the de facto standard for its industry, the network effects of compatibility and standards (combined with the ability to rapidly iterate and optimize the platform) create a significant and lasting competitive advantage that can be nearly unassailable. This dominance lets the market leader “tax” all the participants who want to use the platform, much as levies were imposed in the bygone Republic of Venice. For example, the iTunes store takes a 30 percent share of the proceeds whenever a song, a movie, a book, or an app is sold on that platform. These platform revenues tend to have very high gross margins, which generate cash that can be plowed back into making the platform even better. Amazon’s merchant platform, Facebook’s social graph, and, of course, Apple’s iOS ecosystem are great examples of the power of platforms.