title: Microsoft.IdentityModel vs System.IdentityModel
body: <p>I'm working on a claims-based authorization system using Forms Authentication and ASP.NET MVC 2. I see that one namespace "Microsoft.IdentityModel" provides a lot of the same things as the other "System.IdentityModel". </p>
  
  <p><a href="http://msdn.microsoft.com/en-us/library/system.identitymodel.claims.aspx">System.IdentityModel</a> </p>
  
  <p><a href="http://msdn.microsoft.com/en-us/library/microsoft.identitymodel.claims.aspx">Microsoft.IdentityModel</a></p>
  
  <p>Why do these 2 namespaces exist seperately, when the functionality appears to overlap?</p>