This article from the April 2014 edition of the Palm Beach Bar Bulletin explains (a) Tor and its practical applications to use the internet anonymously and (b) two recent cases, U.S. v. Kim (Harvard bomb-threat case), and U.S. v. Post (location metadata lead to child pornography arrest).
The article also discusses: What is Tor and Is It Legal? Why Do I Need to Be Anonymous? Why Don’t We Use Tor as a Default? Can’t the NSA Already Crack Tor? Lessons from Mr. Kim and Mr. Post.