Microsoft has announced the release of Windows Live ID Web Authentication. This means that WLID (formerly known as Passport) is now opened to third party websites to use as their authentication system. Any Windows Live user can potentially log in to a website that implements Web Authentication. Interestingly sample implementations are available in the Ruby, Python, Perl, and PHP open source languages amongst others — tested on openSUSE 10.2 but expected to work on any platform that supports these languages. More details are available in the SDK documentation.