The ASP.NET Identity System is a modern framework designed for managing authentication and authorization in ASP.NET applications, offering enhancements over previous models such as ASP.NET Membership and Simple Membership. It supports non-relational data stores like Couchbase Server and includes features such as profile store, role and claims-based authorization, social logins, and OWIN support. The Couchbase ASP.NET Identity Provider, currently in Developer Preview, aims to be a comprehensive solution by incorporating these features, although only authentication has been thoroughly tested so far, with plans to expand to role and claims-based authorization and third-party social media integration. The blog post provides a guide on integrating the Couchbase ASP.NET Identity Provider with an ASP.NET MVC Web Application, including steps to replace the default Entity Framework Identity Provider with Couchbase's, and details the use of JSON documents and manual indexes for data storage. Users can access the provider through NuGet or build it from the source on GitHub, and they are encouraged to contribute or report issues via GitHub or Jira.