Hugh Pickens writes "Warren Buffet once said that the best businesses were economic castles protected by unbreachable moats. Now, Erick Schonfeld writes that if search is Google's economic castle, Android is a moat, Chrome browser is a moat, and Google Apps is a moat — all free products, subsidized by search profits, intended to protect the economic castle that is search. 'Android, as well as Chrome and Chrome OS for that matter, are not "products" in the classic business sense. They have no plan to become their own "economic castles,"' says Benchmark Capital VC Bill Gurley. 'They are not trying to make a profit on Android or Chrome. They want to take any layer that lives between themselves and the consumer and make it free (or even less than free).' So don't measure the success of Google's new businesses by how much revenue or profit they generate directly but measure it by how much they shore up Google's core search business. 'Google is ... scorching the earth for 250 miles around the outside of the castle to ensure no one can approach it. And best I can tell, they are doing a damn good job of it.'"