It is becoming clear to me that we are heading into a bloody period of competition that could be extremely unfriendly to the interoperable web as we know it today. If you've followed my thinking about Web 2.0 from the beginning, you know that I believe we are engaged in a long term project to build an internet operating system. I've outlined a few of the ways that big players like Facebook, Apple, and News Corp are potentially breaking the "small pieces loosely joined" model of the Internet. But perhaps most threatening of all are the natural monopolies created by Web 2.0 network effects. We're facing the prospect of Facebook as the platform, Apple as the platform, Google as the platform, Amazon as the platform, where big companies slug it out until one is king of the hill. And it's time for developers to take a stand. If you don't want a repeat of the PC era, place your bets now on open systems. Don't wait till it's too late.