Microsoft Can Remotely Kill Purchased Apps
Meshach writes "The terms of service for Microsoft's newly launched Windows Store allows the seller to remotely kill or remove access to a user's apps for security or legal reasons. The story also notes that MS states purchasers are responsible for backing up the data that you store in apps that you acquire via the Windows Store, including content you upload using those apps. If the Windows Store, an app, or any content is changed or discontinued, your data could be deleted or you may not be able to retrieve data you have stored."
Then they'd be no more different than the iOS App Store is from the Mac App Store. Those have roughly the same rules and the same pricing ($99 per year plus 30% of revenue), with one difference: in Mac OS X 10.7 you still don't have to jailbreak or join the developer program to run your own software on your own machine. Microsoft has indicated that the Windows Store will be the only way to obtain Metro Style apps; this probably means that joining the developer program (required for sideloading) will likewise cost money.