Microsoft has never shown much skill at selling consumer hardware, with the possible exception of its XBox game console, although Rubin pointed out that Apple had no experience selling music gadgets before iPod. And Apple could short-circuit Microsoft by adding a subscription component to iTunes; Steve Jobs has acknowledged that such a move may one day become necessary.

But with stakes this high, Microsoft is likely open to trying virtually any tactic. And as many competitors -- including Apple -- have learned in the past, it's not wise to underestimate Microsoft when it wants to gain control of a market segment.

David Haskin is a freelance writer specializing in mobile and wireless issues.