Google's schedule for its forthcoming I/O conference reveals details on two possible Android features: Voice Access, which will allow users to manage their apps via voice commands, and Nearby, which will allow users to communicate and link to other Android devices in close proximity. Google

Google now receives more searches from mobile devices than desktops in the U.S. and nine other countries, the tech company said Tuesday during a presentation for marketers on Tuesday in Half Moon Bay, California, where it also announced several new ad formats and analytics tools designed for mobile devices.

The shift in Google user behavior is a reflection of the adoption and rise of smartphones since 2007. As more users spend more of their total screen time on mobile devices, it's likely the ad money marketers spend on search -- expected to be nearly $82 billion this year, according to eMarketer -- will soon follow too.

Mobile search in the U.S. is expected to be worth nearly $13 billion, with Google taking about two-thirds market share, eMarketer said. This is why other players in the search market, including Yahoo, numerous startups and possibly Apple as well, are making serious plays to land users' mobile queries.

To reflect this shift, Google has been coming out with more mobile search advertising formats and analytics tools for marketing. The company introduced more of these on Tuesday, including car model ads with high-quality images, hotel ads that include room rates and tools that show marketers how their ads work across different kinds of devices.

"Billions of times per day, consumers turn to Google for I want-to-know, I want-to-go, I want-to-do, and I want-to-buy moments. And at these times, consumers are increasingly picking up their smartphones for answers," the company said in a blog post announcing the new features.