Heh? Its not first time an open source project developed in Microsoft technologies.
Mono, .netnuke, etc are successful open source projects developed in Microsoft technologies.
We are making complete source code, designs and everything available open to
the world, that's the condition to be a project open source.
Most of our developers are working in Microsoft technologies and we are more comfortable on it. So we decided to do it in .net. We know that most of open source developers love to work in open source tools.
Don't worry, a version of the same product is under development in python.