CWmike writes: Google isn't talking publicly about reported plans to sell a powerful Android-based smartphone called the Nexus One directly to consumers next year, but the idea is already raising eyebrows with analysts. The chief concern is that selling an unlocked phone directly to consumers, probably online, could be twice as expensive as buying one through a carrier. The unlocked approach has largely failed in the U.S., with the world's biggest phone manufacturer, Nokia, doing poorly with the concept. Nokia recently announced that its two direct-sales stores in Chicago and New York will close early next year, while online sales of unlocked devices will continue. Conceivably, Google could offer its phone at a price comparable to a subsidized phone from a carrier — as long as customers agree to receive mobile ads on the devices. Since advertising is central to Google's revenue model, that approach might make some sense, analysts said. "Google doesn't want to be in the phone business or the mobile carrier business, so this must be about something else, and that's the advertising business, since Google is in the business of selling ads," said Kevin Burden, an analyst at ABI Research. In one mobile advertising model being tested in Germany, users agree to receive a certain number of ads on their phones to reduce their monthly cellular and texting rates, although reducing the up-front cost of the actual device is relatively novel. Reinforcing the idea of using mobile advertising with direct sales of unlocked phones, Google bought AdMob in November.