To further their effort to keep your information private, Facebook is now requiring applications to request your permission to access anything that is not public. If the application wishes to access your birthday to send you are card, it must explicitly ask for that bit of private information. However, current applications users have running are grandfathered in and are exempt from this new rule.
With this new authorization process, when you log into an application with your Facebook account, the application will only be able to access the public parts of your profile by default. To access the private sections of your profile, the application has to explicitly ask for your permission.
This move was a long time coming after being announced last August. Facebook continues to work with the Privacy Commissioner in Canada in efforts to stem privacy-related lawsuits.