On Tuesday Microsoft revealed an app store for Windows 8 apps. Some of the features being touted by Microsoft's Antoine Leblond at the time included an app discovery system inside and outside of the online marketplace, built-in app trials, support for x86 and ARM-based hardware, and a flexible business model. What he didn't talk too much about were the store's new terms of service. A section of it informs users that the company reserves the right to remotely "kill" or "remove" access to apps for security or legal reasons.
Microsoft explains it in its terms of service under "Can Microsoft remove apps or data from my device?"
"We may change or discontinue certain apps or content offered in the Windows Store at any time, for any reason." Sometimes, we do so to respond to legal or contractual requirements. In cases where your security is at risk, or where we're required to do so for legal reasons, you may not be able to run apps or access content that you previously acquired or purchased a license for."
"In cases where we remove a paid app from your Windows 8 Beta device not at your direction, we may refund to you the amount you paid for the license. Some apps may also stop working if you update or change your Windows 8 Beta device, or if you attempt to use those apps on a Windows 8 Beta device with different features or processor type. You 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. We have no obligation to return data to you. If sign in information or other data is stored with an expiration date, we may also delete the data as of that date."
Microsoft also tells users in the terms of service that there is no "cooling off" period where consumers have the right to "return" an app they paid for to receive a refund, unless "permitted by state law." Google's Android Market has a "cooling-off period" of just 15 minutes.
You can read them for yourselves at Microsoft.com.