The California Court of Appeal has just held that, under the Stored Communications Act, service providers need not — and may not — turn over the contents of subscriber e-mail when those contents are subpoenaed in a civil case, unless the subscriber consents. (Warrants and other court orders in criminal cases are another matter.) This came in the same case, O'Grady v. Superior Court (Apple Computer, Inc.) that I discuss below.

UPDATE: Added the "unless the subscriber consents" clause; I at first omitted it because I thought it went more or less without saying, and that the controversies arise precisely when the subscriber doesn't want the information turned over. But, prompted by the first comment posted below, I thought I'd add the clause for the sake of precision.