Apple reportedly is in talks with Microsoft to make Bing the default search engine on the iPhone's Safari Web browser, according to Business Week. The idea may sound surprising, but it shows how deep the ongoing battle between Google and Apple (which started after the Google Voice iPhone application was barred entry into the iTunes App Store) has become.

But would Apple be hurting itself by forcing the less popular Bing on its customers, and exactly how far would an Apple-Microsoft deal go? Here are the 5 questions that come to mind:

First Bing search, but what's next?

The iPhone doesn't just use Google as the default search engine for its browser, but also comes with default applications for Google services such as YouTube and Google Maps. Microsoft would be hard pressed to come up with a competitor to YouTube since it recently shut down its Soapbox video site, but Maps is another matter. Last month, Microsoft launched improvements to Bing Maps including Streetside, which is similar to Google Street View, as well as extra layers of data like weather, Wikipedia entries and "applications" for traffic and local information.

If Apple is doing a search deal with Microsoft, could it mean a deal for Maps and other services as well?

Does this mean Silverlight is coming to the iPhone?

If, and this is a big if, Microsoft and Apple really do a deal for anything beyond search on the iPhone, that may be the final nail in the coffin for Adobe Flash on the iPhone. You can bet that Microsoft wouldn't mind using talks with Apple to try and push Silverlight's competitor for video animation off of Apple's radar. Since Apple's disdain for Flash is well known, would Jobs & Company be willing to go that far with Microsoft?

Does this really hurt Google?

In the short term, Google might feel some minor financial pain from not being the default search engine on the iPhone. AdMob, a mobile advertising network that Google recently offered to buy for $750 million in stock, routinely says the iPhone and iPod Touch are the two leading devices for U.S.-based mobile search queries. So unless iPhone and iPod Touch users manually switch their browser's default search engine back to Google, the search giant will probably lose some ground in mobile searches.

However, even though many predict a big future for Internet-capable mobile devices, the fact is the vast majority of Google's search traffic still comes from desktop and laptop PCs. Also, the iPhone and iPod Touch may be popular now, but Google is moving aggressively into the mobile space with an ever-expanding list of devices running the company's Android platform. AdMob recently said worldwide requests from Android devices grew by 97 percent between October and December of last year, with over one billion ad requests from Android devices just in December 2009. Search queries from Apple devices were still greater during that time, but it's clear Android is gaining some serious ground in the mobile device market.

What does this mean for iPhone and iPod Touch users?

If the deal goes through, then iPhone and iPod Touch users will actually have greater choice when it comes to in-browser search engines. Right now, Safari in the iPhone only offers Google and Yahoo, so adding Bing, the third-most popular search engine, may have been a foregone conclusion anyway. Besides, if you're not satisfied with Bing, you can manually switch back to Google anyway. The biggest difference would be if Apple's talks with Microsoft go beyond search and reach into some of the iPhone's standard applications.

If you're a Google user, but you couldn't be bothered to switch your browser's search engine, another alternative would be to rely on Google's iPhone app--Bing recently launched an iPhone app as well.

What's Apple's Game Plan Here?

There may be more to Apple's plans than just trying to stick it to Google. Business Week is reporting that Apple has an ongoing "skunk works" project looking at building its own search engine. So Apple may be using Microsoft to slow down Google, while Cupertino develops its own Google-killer. As one anonymous source told Business Week, "Apple and Google know the other is their primary enemy . . . Microsoft is now a pawn in that battle."

Microsoft is being used as a pawn? Now that's something you don't hear every day.

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