With this purchase, along with the Skype purchase, Microsoft owns the hardware the user has, the operating system it uses, the calling software and user base.
But will they have enough money to buy a mobile network after all this is said and done? Would be pretty interesting to see them buy someone like Sprint.
I doubt it will happen, but in combination with each other the two acquisitions make more sense than on their own. Skype+Nokia+Windows Phone 7 would allow Microsoft a similar strategic position to Android+Google Voice. Owning everything short of a carrier allows for better integration of services. They've already got a superior content delivery marketplace with Xbox Video Marketplace/Zune. They've got most of the pieces of something special, but it hasn't coalesced into much yet.
Many seem to be under the mistaken impression that the acquisition had something to do with the (rather commonplace) technology Skype uses, and not the bazillion people who use it routinely and treat it as if were synonymous with VoIP.
To me the Skype acquisition is great for the industry but bad for Microsoft. I think they're probably going to just waste it; maybe put Skype buttons in Outlook or rename it Windows Live Chat or something.
It's good for the industry because maybe, finally, it'll be the factor that causes a cross-platform video solution to be adopted by the major players.
Best case scenario for Microsoft is they hold fort and just don't make any money off it. I'd love to hear why you think this is good for them.
Large user base; proven and useful technology. Most Skype users find a value in it (I do think there's more money to make than what has been made so far). In the end it's a technology that could help brighten Microsoft's image.
If they manage to integrate it gracefuly in their office & collaboration stack, without ruining it as a standalone product, it may very well be a winner for them.
Indeed the challenges are huge but I believe this is the right time for challenges at Microsoft.