Just when you thought it was a straightforward either/or choice – go with an iPhone app or an Android app or both – suddenly all the choices are in flux as Google's announcement Monday that it would acquire Motorola Mobility for a staggering $12.5 billion, 63% above the stock's closing price on Friday (trading as MMI), roiled the mobile world.

“Motorola's total commitment to Android in mobile devices is one of many reasons that there is a natural fit between our two companies. Together, we will create amazing user experiences that supercharge the entire Android ecosystem for the benefit of consumers, partners and developers everywhere,” Google CEO Larry Page said in a statement.

Motorola Mobility is known for making cellphones that run on the Android platform (such as the popular Droid) and it also was among the first to market with a tablet device – Xoom – running the Android Honeycomb operating system that is specifically designed for tablets. 

Google, for its part, is the developer of the Android operating system which has emerged as the primary rival to Apple's iPhone.

Although Page stressed that going forward Google will remain committed to running Android “as an open platform” – that is, available to any smartphone or tablet manufacturer – initial market reactions indicate that beneficiaries of the deal may include Nokia and Microsoft, as other phone makers apparently express skepticism about just how open Google will remain. 

This also is boosting interest in the Windows Mobile operating system – which most analysts had written off for dead as recently as last week.

The Google-Motorola deal “could prove to be a massive catalyst for the Windows Phone ecosystem,” James Etheridge, a spokesman for Nokia, said in an e-mail to Bloomberg news.

Most experts seem to believe it is way too early to draw conclusions about impacts on the smartphone universe. But an upshot may be that institutions contemplating where to put their apps development dollars need to take a fresh look at the possibility of a widening universe of choice.