Design Facebook to be more secure, private, and intimate.

Whether you see Facebook Groups or Newsfeed - through its products FB tries to connect millions of users, helps them form their own communities and stay in touch. How can we bring the same sense of community and engagement but in a more secure, private and intimate way? Walk through some user groups which could fall in the purview of this., identify some of the user needs for these groups and then come up with some ideas to help solve this problem?