Hazardous Half Lives on Facebook

OK -I swore I would not write one more thing about Facebook, but here goes...
There are some long-term consequences that no one can adequately predict about Facebook postings. I am reminded of nuclear half lives--not that I pretend any special knowledge of nuclear physics--I leave that to our Mr. "Discovering Science". According to my old Webster's (how's that for an ironic title?) a half-life is the period required "for the disintegration of half of the atoms in a sample of some specific radioactive substance."
Well, people are discovering that their past lives are still "radioactive" too, as the author of "Growing Up On Facebook" notes (New York Times, 15 March 2009): http://www.nytimes.com/2009/03/15/magazine/15wwln-lede-t.html?_r=1&scp=1&sq=Growing%20Up%20On%20Facebook&st=cse. Someone who hadn't seen her in decades posted a picture of her at age 16. Sure glad that I have always been averse to having my picture taken, especially by strangers! Some very interesting statistics are posted in the article: the age 25-50 category topped the charts at 3 + hours for the average time spent on Facebook during January, 2009. Nostalgia? Narcissism? Both?
How about authentic self-invention? There is something tragic about the apparent need in our society for the creation of an alternative "self" and transmission of same to the rest of the world via impersonal means.
More practically, a related phenomenon is that fact that all this may eventually cost people lots and lots of money far down the road. The potential impact of the "half-life phenomenon" of published private information on job-hunters is already well-established. College kids, whatever you do, don't let anyone snap that photo of you grinning and naked in the hot tub at that fraternity kegger! It may come back to haunt you more quickly than you think.
An insurance specialist I know adds that sites like Facebook, and the disclosures therein, take on lives of their own once published. They may be exploited by insurers seeking to limit their exposure to pre-existing conditions (such as detailed addiction narratives and accounts of personal trauma). In short, his advice is: "Take it to your shrink," or "Save the drama for your mama."
Once our words are out there in the universe, they are no longer our own.