63. C) They don’t know their personal data enriches Facebook.
64. C) To render better service to its users.
65. B) Formulating regulations for social-networking sites.
66. C) He doesn’t want his personal data abused.
点评：
文章的主题围绕当下很受欢迎的社交网站Facebook，揭露其将用户资料出售给广告商。而大多数用户并未意识到这一点，因为他们并没有意识到个人资料的重要性。作者的态度和立场非常鲜明，并表示考虑注销自己的账户。