As a few others have noted, there are a few sites out there (e.g., Google's crisis response
) that seek to match people in need with responders.
If this were any other application, I would argue that competition is good, but I fear that the fragmentation of services for disaster relief ultimately puts more lives at risk. Why doesn't Microsoft through its support & resources behind a well-established, widely-adopted system for collective disaster management? To provide yet another service that is disconnected from all others seems to invite confusion and reduce the power of the network effect.
The only answer I can think of is that Microsoft (lacking the same philanthropic reputation as its competitor, Google) wants to take all the credit. How noble.