Who doesn't want to build their own OS? Cosmos provides all the legos and lets you forget the hard parts of writing low level kernel pieces, and unlike other OS's does not force you into C++. Use C# (or any .NET language), plug the legos that you need, and build your shell!
Most users of virtualization today deploy only a few virtual machines per host. And each virtual machine often performs at least half a dozen tasks. Even if your stated goal is to serve web pages, often the same virtual machine also provides DNS, routing, cacheing, and other functions. This is because the overhead of the operating system alone is quite high, and each host machine can only host so many virtual machines.
With Cosmos you can develop a custom build that performs exactly and only what you need. Need DNS? Make a custom Cosmos build with only the necessary pieces. Then another for SMTP, another for a local database, another for routing, another for SMTP, and so on. With Cosmos you can easily deploy several dozens of virtual machines.
In addition, since the footprint of the OS is quite small, you could easily migrate, even on demand the virtual machine to another host to perform virtual machine load balancing. We also plan special drivers for Cosmos to run in virtualization with the highest available performance. No need for "Virtual machine tools", Cosmos will natively be able to work as a virtual machine.
Deploy mini servers, tiny desktops, or even make farms of "mini blades" using mini-itx or pico-itx boards. Cosmos is ideal for these limited resource mother boards. One might even consider deploying farms of such low cost, low power devices combined with NAS instead of virtualization in certain scenarios.
Need to build a kiosk, internet, or other dedicated computer? Use Cosmos to include exactly and only exactly what pieces you need to secure the computer.
Cosmos is designed to be extremely portable and able to deploy in small footprints. Use Cosmos to build exactly what pieces you need into your embedded solution.
Because Cosmos is designed to be portable, we plan to experiment with the Wii, iPhone, OLPC and more. But feel free to port Cosmos to other platforms that you may need.