From Steve Lohr in the New York Times:
If a stranger came up to you on the street, would you give him your name, Social Security number and e-mail address?
Probably not.
Yet people often dole out all kinds of personal information on the Internet that allows such identifying data to be deduced. Services like Facebook, Twitterand Flickr are oceans of personal minutiae — birthday greetings sent and received, school and work gossip, photos of family vacations, and movies watched.
Computer scientists and policy experts say that such seemingly innocuous bits of self-revelation can increasingly be collected and reassembled by computers to help create a picture of a person’s identity, sometimes down to the Social Security number.
VAIL, Ariz. — Students endure hundreds of hours on yellow buses each year getting to and from school in this desert exurb of Tucson, and stir-crazy teenagers break the monotony by teasing, texting, flirting, shouting, climbing (over seats) and sometimes punching (seats or seatmates).
From Tricia Wang’s blog 
From Walt Mossberg in the Wall Street Journal:
Select findings from a new study by Andrew J. Flanagin, Professor in the Department of Communication, and Miriam Metzger, Associate Professor in the Department of Communication, University of California, Santa Barbara.
Jon Udell’s recent blog post begins,
Facebook just “updated” its privacy settings, and I almost did not notice. That’s because I’m (Facebook founder) Mark Zuckerberg’s nightmare: I don’t “share” anything on Facebook to begin with, so my Facebook profile contains little to be private about.
In 
From Josh Karp, in “Spotlight on Digital Media and Learning.”