5. A Great App Marketplace

One of the initial stumbling blocks for Android was the Market. Not only did it not have as many apps as ITunes, the actual interface was horrible (that’s a technical term.) The new market interface is better but still hard to find stuff.
What about billing? iTunes billing is great, if you have a credit card and an iTunes account. Android again, you need a card and a Google Checkout account. So Microsoft will launch with credit card payments, operator billing, and try before you buy.
The operator billing alone should extend the potential reach of app users (anyone under 18 for starters) and offer another convenient way to buy apps.