Windows 8 provides Windows Store apps with the ability to communicate with any other app on the computer without prior knowledge of what those apps might be through a concept called Contracts. A Contract is an operating system level interface that consumers or providers of information implement. The operating system then keeps track of which apps support which contracts and coordinates the information between apps using those contracts.

Window 8, as part of its focus on improving the trust level in the apps it runs, expects Windows Store apps to communicate the capabilities they need. A Capability is a permission or access right that a Windows Store app requires for it to run correctly, for example, an app that requires Internet access or local network permissions. There is a range of capabilities that the operating system can provide to Windows Store apps. An app that doesn't request capabilities from the operating system will be provided minimum level...