I wish we would treat cyberspace analogues of established property with the same respect given to the original. For example, your e-mail inbox is the online equivalent of your mailbox. Yet, one being "on your lawn" and the other "at Google's data-center," all bets are off. While I believe the Supreme Court should do better job at explicitly addressing this (for instance, "responsible expectation of privacy" established Katz[1] would be a fair test for e-mail, while Jones[2] and Kyllo[3] show the importance of taking modern technology into account), the government needs to firmly establish which techniques are important for security while protecting us from those which recklessly violate privacy.
[1] http://www.law.cornell.edu/supct/html/historics/USSC_CR_0389...
[2] http://www.law.cornell.edu/supremecourt/text/10-1259
[3] http://www.law.cornell.edu/supct/html/99-8508.ZS.html