Includes an entertaining quote from "a postdoctoral fellow at Carnegie Mellon University who studies privacy in social networks" who believes that text content -- tweets, specifically -- can actually be deleted from the internet as long as the Library of Congress doesn't archive them:
"'This is the nature of these systems,' says Mr. Stutzman, who has criticized the Library of Congress's Twitter project. 'Maybe in three years, we'll look at public tweets and say, Oh, my God, those weren't public. A lot of people that are using Twitter nowadays may actually want to go back and delete their accounts or take those things out of the public at a later date, and they no longer can.'"