really what is the difference from outsourcing your IT department, not much :)
So, it will suffer from the same problems of lack of control, and lax security, quite simple really.
But you will have fatboy clients in the form of a desktop that you will still have to support, which have loads of redundant CPU cycles in most machines just begging to be used in a distributed environment.
So, 'cloud technology' will start to be used internally as well, which will lessen the call for external clouds, and it will work better in an organisation than existing external to it.
Right back to my distcc, is the world in yet?