A team was working on this during Lean Startup Machine weekend some years ago. It's an ongoing challenge for managers and SMB's. I'd be curious how this fits into distributed teams and on-demand workforces.
Lots of interesting stuff coming out of microsoft for SMB or personal "business" productivity. Do they have a public mobile design document? They do have their own flavor across android and ios.
I believe we underestimate Microsoft's competitive advantage in this area: with the huge (?) installed base in the SMB sector, I see many service businesses inclined to switch to a free (for them), Microsoft product from some other product. Microsoft previously launched Bookings to help these businesses manage online appointments and bookings, obviously Microsoft is placing a bet on SMBs.
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