The developer preview of WAAD was formally launched on June 7, and was incorporated into the spring release of Windows Azure, according to John Shewchuk, a Microsoft Technical Fellow focusing on Active Directory, in a blog post. However, the developer preview additions that were released this week support a couple of new features. One new feature is a REST-based “directory graph API,” which allows an application to tap WAAD data. The other is a “Web single sign-on” capability that developers can use to build cloud-based applications that will have a single user. Read the full details here.