[andsosayallofus]

Where's the money here? It's not a subscription based service, so what financial sense does it make to dump this data straight to a server?

I can't imagine there's complex data processing being done that a smartphone can't handle, so I assume the data is being sent back because it's somehow useful or valuable to Microsoft.. but how?

[jzwinck]

The network effect. Fitbit has a huge advantage right now because the user base is so large. A lot of people use its social features to compete with their friends, office mates, etc. This encourages more people to buy the hardware to participate.

[orjan]

From a user perspective, it makes sense to upload the data so that you're not constrained to your phone for viewing your info. And Microsoft gets a good use case for Azure - I imagine they might use this in promoting Azure services.