Microsoft security experts have never really been fans of SAML, a markup language, that is crucial to many e-government initiatives and SSO models. The problem with SAML is that it is obese and almost no one had a full implementation of it until recently, yet it was always Microsoft that receive the brunt of the criticism for not supporting it. Well I’m happy to say that a lot work was put it to address shortcomings of SAML support and ADFS 2.0 is fully interoperable with SAML 2.0 implementations.
Microsoft still thinks that SAML is over-defined and that WS-* and WS-Federation protocols are better all around, however, SAML interop is a fact of life in does industries and people should no longer have excuses for adopting our federation solutions especially in heterogeneous computing environments.
NetworkWorld has a great in-depth article on this new development!