• by Mark Walsh  @markfwal, April 28, 2010

Screenshot: LabPixies.com.

As their mobile war broadens, Apple and Google aren't just slugging it out with competing ad networks, operating systems and devices. They're both also stepping up their push into mobile applications through respective new acquisitions in the space.

Apple's purchase of startup Siri is the more intriguing of the two deals because it signals the company's first foray into local search -- and Google's backyard, so to speak. Siri has built a free portable assistant app for the iPhone that can help users do things like find the closest Starbucks, see what movies are playing nearby or make reservations at the local steakhouse.

The application's voice-based system allows people to simply ask questions into their phones, like "What funny movies are playing near my home this weekend?" or "Where can I find parking near Laguardia Airport?" Siri's business model involves taking a cut of the transactions it facilitates.

"It can be seen as a 'search' play, a voice play or as a pure'artificial intelligence' technology acquisition. Siri is all about local search right now but doesn't necessarily have to be limited to that in the future," said Greg Sterling, a senior analyst at Opus Research.

Other options might include adding a social layer to the app, such as a Foursquare-like service for "checking-in" at locations. Apple could also find a way to integrate display advertising into the app through its new iAd platform.

But Sterling said the Siri deal isn't necessarily a direct strike at Google's search empire. "Many people want to interpret this in the context of a competitive move vs. Google and there's probably some truth there, but Apple has independent reasons for buying the company as well," he said.

Apple CEO Steve Jobs took a shot at Google, though, during the iAd unveiling this month when he said that on mobile,"Search is not where it's at, people are not searching on a mobile device like they do on the desktop." But apparently, search wrapped in a voice-based app is where it's at.

For its part, the search giant has snapped up Israel-based mobile app developer Labpixies for a reported $25 million. The company has created Android and iPhone games including Flood-It!, Line-Up and Trio, as well as developing widgets for the iGoogle home page personalization program. Google said the Labpixies team would lead iGoogle efforts across Europe, the Middle East, and Africa.

Separately, Google this week rolled out a mobile-optimized version of its Place Pages service, providing Web pages for businesses within Google Maps, to make it easier for people to access local information on the go. And last week, the company expanded its Search by voice feature to Windows Mobile and Symbian S60 phones. Take that, Siri! The mobile Clash of Titans continues...