One thing that has slowed the evolution of a rich, open source web development ecosystem on the .NET platform has been over-dependence on IIS and the ASP.NET framework. OWIN specifies an open HTTP handling interface that decouples web server from application much like Rack has done for the Ruby community. We are excited about OWIN because it opens up the possibility of new .NET web development tools composed of simple, independently-developed modules. Nancy is the perfect example of this. We also hope it will increase the practice of deploying web applications as standalone, self-hosted services on the .NET platform.