The short answer is yes.
I hope the answer to this question is no. Nearly twenty years ago, Robert Redford starred in a movie about hackers. One scene in the movie shows them decrypting the phrase "No more secrets." The recent Pennsylvania case Largent v. Reed (Pa. Common Pleas Nov. 8, 2011) proves this is a reality of the Internet Age. In Largent, the defendant asked the judge for access to the plaintiff's Facebook account so he could prove that she was exaggerating her injuries. The judge ruled that plaintiff's access to Facebook was not protected under various statutes and granted defendant 21 days of access to plaintiff's account.