Most developers working today in Silverlight probably have an ASP.NET background. I personally started with ASP.NET development way back in 2001 with the very first version of the platform. Over time, the ASP.NET platform evolved immensely and gathered some great features. One of these nice additions to the platform is the ASP.NET Membership API, introduced with ASP.NET 2.0. This API allows us to manage user authentication, role management and user profiling with ease. With ASP.NET 3.5, Microsoft added the so-called ASP.NET Application Services to make it possible to use this API from client-side technologies.