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

“Motorola's total commitment to Android in mobile devices is oneof many reasons that there is a natural fit between our twocompanies. Together, we will create amazing user experiences thatsupercharge the entire Android ecosystem for the benefit ofconsumers, partners and developers everywhere,” Google CEO LarryPage said in a statement.

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

Google, for its part, is the developer of the Android operatingsystem which has emerged as the primary rival to Apple'siPhone.

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

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

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

Most experts seem to believe it is way too early to drawconclusions about impacts on the smartphone universe. But an upshotmay be that institutions contemplating where to put their appsdevelopment dollars need to take a fresh look at the possibility ofa widening universe of choice.