Some 150,000 chosen businesses (which must already have joined Google’s Local Business Center) have been mailed a “We’re a favorite place on Google” decal with a unique bar code to put in their store windows. Potential customers walking by the store can scan the bar code with their phones (for instance, using Android’s bar code scanner or the QuickMark app for the iPhone — which usually costs 99 cents but will be free to the first 40,000 phones that download it starting Monday) and bring up the business’ Google page.

Liz Gannes has a great article about Google and Twitter/CitySearch racing to acquire local businesses’ online advertising revenue, the implications for Yelp and asks the key question:

“With Google and Twitter zeroing in on this space simultaneously, who wants to take bets on how many hours till Facebook Local launches?”