Suggesting that all the software that supports cloud computing needs to be open source, leaves no room for a business that wants to innovate and capitalize on IP created to enhance the cloud computing effort.
It seems that IBM is one of the key players behind this manifesto. IBM has long been a strong proponent of Open Source as, for a consulting and services company, software is a cost in their business model. Reducing this cost to closer to zero is something they must strive for. As a software developer I like to get rewarded for the software I create and innovate.
Reading the manifesto it seems to be a very limiting concept; blocking innovation of new programming models, blocking innovation of new protocols and blocking the independent innovation of cloud technologies.
While I can see advantage in defining some standards for protocols I think we already this with W3. It is not clear to me what this manifesto adds to the cloud computing world.