The System.Web.Routing assembly that introduced with .NET 3.5 SP1 brings lots of good stuff to the ASP.NET developers. It was originally part of ASP.NET MVC. There are lots of posts regarding the usage of ASP.NET in Web Form Applications. Check out the posts of Phil Haack and Chris Cavanagh for samples and lots of useful stuffs. In this post I don’t want to repeat that samples. Here I am going to talk about What URL Routing is and why somebody may want to use it. When you are using Routing, you can use URLs that do not map to a physical file. Because the URL does not need to map to a physical file, then you can use URLs that have more meaning for the users and search engines.