Katana is not a revolutionary new project in ASP.NET world. It is just a next step in ASP.NET, The points that drive to go for Katana and OWIN are, Basically ASP.NET was optimised for two types of customers one classing ASP developers and second one LOB(line of business app) developers. From the beginning it was expected to run these applications under IIS(internet information services). Challenges are, as ASP.NET is part of .NET Framework which is shipping in every two to three years and the Web is moving little faster than .NET FW. How do you get these new web concepts faster to customers? The way that ASP.NET was built everything was put in to one assembly System.Web. It is highly coupled. More over all the features in this assembly are turned on by default, you have to explicitly turn it off for those features that you do not like. There is only one hosting option ie IIS.