Hi Chris,
Applications that support the Share contract should not depend on specific applications being an available Share Source or Target. There is no guarantee that the user installed it and and there is no way for an application to query
information about other Share apps on the system. Users can have a wide variety of applications that can be shared to from 3rd parties including mail, social, and editing apps. Application developers are encouraged to provide data in multiple formats
when supporting the Share contract for this very reason.
Thanks.