Shared Office Space

I'm a bit intrigued by the shared office workspace being pitched by PivotDesk at Seattle Tech Meetup. Seems to take the contract management and billing hassles out of subletting office space, coupled with the host office providing other services (utilities, high speed internet, conference room, etc) which might not defray actual overhead costs.

Certainly there are far more pros than cons for the Guest; I'm not sure what else the Host office gains out of this arrangement other than a monthly sublet fee paid to them.