Interesting article (link attached here) reporting case in Manhattan on July 2nd whereby Twitter ordered to turn over some of deleted tweets of a user who was arrested in October 2011 during an Occupy Wall Street demonstration. Although Twitter opposed the application, the Judge remained firm except to limit what the State could get from Twitter without a warrant.
The Judge ruled that content less than 180 days old required a warrant however for the purposes of the trial, the State have achieved that it wanted i.e tweets from September 15 to December 30, 2011, including ones that he deleted.
In summary the case concerned a prosecution for trespass and prosecutors believe the demonstrator was tweeting about an issued he was trying to use in his defence and that in fact his tweets may contradict his defence.
The judge stated “If you post a tweet, just like if you scream it out the window, there is no reasonable expectation of privacy”.
Twitters policies at the time stated that the social media channel, not users, owned all tweets and enjoyed the rights to distribute them”. Since then twitter has changed its terms of service to more clearly indicate that tweeters own their tweets.