A smartphone showing the first twitter message of Pope Benedict XVI in Italian is held in front of a computer showing the logo of Twitter on December 12, 2012 in Rome.
Last year an Occupy Wall Street protestor named Malcolm Harris was arrested for unruly conduct during a march in New York City. Harris claims he did nothing wrong, prosecutors say his tweets tell a different story.
The problem is, Harris deleted those tweets, and the only remaining copies are in Twitter's archive. The question now: Who owns those tweets, Twitter or Harris?
If something is deleted from the Web, can you expect it to be off the record or can prosecutors still use it against you?
To explain we're joined by Jennifer Granick, director of Civil Liberties at Stanford's Center for Internet and Society.