For ordinary customers, software that's not on the Mac App Store might as well not even exist. Developers who try to make a living selling serial numbers on the web via Paypal are going to be selling to a tinier and tinier slice of the market. We're headed toward appliance computing for almost everybody and a Linux box for the rest of us.

Apple understands this; hell, even Microsoft is starting to understand this. Does anyone doubt that we're headed in the same general direction on the Windows Store?