Given that Sun, DataSynapse, Platform etc all have grid solution, Microsoft is definitely starting from the back of the pack. From an investment banking perspective, almost every major tier-1 bank created its own cluster-compute-grid application during the last 10 years. With a number of these tier-1 investment banks having already migrated from their home grown solution to commercial grid software its hard to envisage a bank migrating again to Microsoft's Compute Cluster Solution. If we assume there are a few Microsoft centric investment banks still with home grown grids, then Microsoft should be able to sell their product in a few investment banks
It seems to me that Matt is missing the point about what CCS is all about.
Remember, CCS is an operating system with a set of low-level tools that enable some of the things necessary for scientific, technical, and high-performance computing. (MPI, support for high-bandwidth interconnects, etc.).
Microsoft's operating system has a stranglehold on the desktop OS in the world, but they're making a concerted effort to increase their market share on the servers (although they're probably doing better than you think; according to IDC, Microsoft is still shipping OSs on about three times as many servers as Linux). CCS is their move to counter the strong growth that Linux has been making in that space, and to make sure that Windows is a viable alternative to UNIX for the scientific and technical applications.
Is an OS enough to do this? Of course not. Microsoft, as always, needs partners to help them in this space. From the beginning, they have fostered partnerships and encouraged developers to work on their platform. They build the foundation, and we do the rest. I'm glad they continue to improve that OS (and the awesome development tools), making it a great platform to develop software on!