Facebook apps don’t just disclose information about the user who happens to fire them up. They also disclose information about that user’s friends. Surprise! You agreed to this.
These apps will disclose not just email addresses and names of friends, but such things as location, sexual preference, religion, political orientation, birthdays, photographs and a host of other things many Facebook users thought they were not disclosing under a privacy setting. But disclosure is approved under the terms you agreed to on Facebook.