C# is completely different than Java. Know what you speak of.

Yes, people buy Windows Phone 7 based phones. In fact they're always topping in reviews and happy customers.

I'm glad to see they chose Nokia Lumia 920 as a phone. It is very powerful, sleek and well-done smartphone with enterprise features from Microsoft. It's really much better business phone than iPhone or Android-based smart phones. On top of that Yahoo can use Visual Studio to develop their own apps - all with the maturity and familiarity of C# and Windows programming. Great choice!