The System.Net team has put together a list of frequently asked questions for the System.Uri class that they're responsible for. The Uri is one of the few types that we use quite extensively in the programming model for WCF but don't implement ourselves. There are a small number of features that have been added to Uri at our request though. Next time I'll talk about the scheme parsers for net.pipe and net.tcp mentioned in question 6 to demonstrate one of those features.