This document discusses the evolution of membership providers in ASP.NET, from ASP.NET 1.1 which had no membership provider, through ASP.NET 2.0, 4.0, 4.5 and the latest ASP.NET Identity. It provides an overview of the key features of ASP.NET Identity 1.0 and 2.1, including user profile customization, testing, social authentication, Active Directory integration and extensibility. Examples of storage providers other than SQL Server are also listed. The document encourages reviewing the ASP.NET Identity documentation and code samples to learn more.