Let me give you this hypothetical about privacy. You and a friend walk into a public subway station having a conversation about how much you hate your boss.

"Facebook is officially 'out,' as in uncool, amongst partners, parents and pundits all coming to the realization that Zuckerberg and his company are - simply put - not trustworthy," Calacanis wrote on his personal Web site.

First off, one big caveat: It is simply impossible to have the old Facebook experience with the old level of privacy. If you want the old level of privacy, you're going to have to give up some functionality; if you want all the old functionality, you're going to have to give up some privacy.

In a new study to be released this month, the Pew Internet Project has found that people in their 20s exert more control over their digital reputations than older adults, more vigorously deleting unwanted posts and limiting information about themselves. “Social networking requires vigilance, not only in what you post, but what your friends post about you,” said Mary Madden, a senior research specialist who oversaw the study by Pew, which examines online behavior.