Like Microsoft's recent billion-dollar-plus investment in Nokia, analysts speculated that Microsoft is probably paying RIM "boatloads" for the partnership deal, although Microsoft would not reveal any terms.

The announcement Tuesday that Microsoft is "going to " came from CEO Steve Ballmer in a surprise keynote appearance at BlackBerry World in Orlando, Fla.

Immediately, several analysts noted the importance of the move, given the growth in and the use of mobile search in advertising and location-based purchasing.

"This shows that the battle for mobile search is on," said Michael Gartenberg, an analyst at Gartner and a Computerworld columnist, in an email.

"Ballmer's presence at BlackBerry World is a great example of the enemy of my enemy is my friend," Gartenberg said. " indeed is the enemy in this case."