• by Laurie Sullivan  @lauriesullivan, May 10, 2010

Google search volume, an inviting developer platform, and the sheer number of mobile handsets running the Android operating system (OS) will keep smiles on the faces of Google executives for a long time. The NPD Group released numbers Monday that put Android in the No. 2 position for market share in the U.S., as the search engine turns its focus on Google I/O, an event in San Francisco where the search engine will host technical sessions and lectures around Google Web Toolkit, APIs, Android and Chrome.

Android OS ended the quarter with 28% market share, up from 20% sequentially, according to The NPD Group. Expect that to continue, says eMarketer senior analyst Noah Elkin. There's one iPhone, but there are many Android handsets coming to market. And all the U.S. carriers continue to put marketing muscle behind them. "There's about 100 new Android devices in the pipeline scheduled to launch this year worldwide," he says. "So, Android has nowhere to go but up."

Carriers also give stuff away related to Android. There's a big demand for smartphones, but consumers are still looking for a good deal. A free Android smartphone is still more appealing than a $200 Apple iPhone, Elkin says. When Apple's Steve Jobs announced iAd, he made a reference to applications being a way that people search for information on smartphones, rather than search.

Since then Apple bought Siri, a company that does voice search on mobile -- signaling that Apple plans to challenge Google in mobile search, but in a slightly different way. Siri taps into speech-to-text technology and artificial intelligence, allowing consumers to say what they want to find.

Elkin says handset manufacturers and developers like to work with Android because there are fewer restrictions. Hardware and software development can stay under one roof. "You have to remember that Apple came this far with one phone, and there are no others that have done this," he says. "For Google, Android made the progress with multiple devices."

The proprietary position Apple took will keep Android market share building, however, The Android OS ended the quarter with U.S. market share of 28%, up from approximately 20% in the December quarter, according to NPD. The firm attributes the increase to strong sales of handsets like the Droid and Droid Eris at Verizon Wireless. That compares with Apple's iPhone that held steady at 21% in the U.S. Research In Motion (RIM) remains in the No.1 spot. RIM's BlackBerry family of smartphones owns 36% of the market.