Facebook:
A customizable public profile. Facebook allows a user to participate in a unique network comprised of their family and friends. The NewFeed feature makes user uploaded content available to their whole network, as well as providing instant insight into events unfolding within the community.
http://failbook.failblog.org/2011/11/06/funny-facebook-fails-your-grandparents-are-lost-in-the-digital-world/