You can now more easily enhance applications to gather and store data about the user, even if he or she is not authenticated, by enabling Profile properties for anonymous use. And when the user returns to the site, the Profile information will still be available. In addition, when a user chooses to authenticate, he can do so directly from the browser without a series of redirects to a login page and back.
Enabling the application services for AJAX is an important step forward in being able to write richer browser-based applications that take full advantage of the server and to enhance the user’s experience. The application can seem more dynamic and responsive by reducing the need to do a full postback and refresh of entire pages.