Prius on Tuesday, promising that improvements in the battery, engine, wind resistance and weight mean better mileage for the world's top-selling hybrid car. A minor mystery in the auto world is why Toyota, after making the world’s first popular hybrid (the Prius), didn’t capitalize on its technological lead to surge into fully electric cars. Plus, Google recently announced that it wants to be carbon neutral by the end of 2007, though it's not the first company to make such an announcement. Whil...