The resounding win by a Google artificial intelligence program over a champion in the complex board game Go this month was a statement -- not so much to professional game players as to Google's competitors. Many of the tech industry's biggest companies, like Amazon, Google, IBM and Microsoft, are jockeying to become the go-to company for A.I. In the industry's lingo, the companies are engaged in a "platform war." A platform, in technology, is essentially a piece of software that other companies build on and that consumers cannot do without. Become the platform and huge profits will follow.