Title I of the ECPA protects wire, oral, and electronic communications while in transit. It sets down requirements for search warrants that are more stringent than in other settings. Title II of the ECPA, the Stored Communications Act (SCA) protects communication held in electronic storage, most notably messages stored on computers. Its protections are weaker than those of Title I, however, and do not impose heightened standards for warrants. Title III prohibits the use of pen register and/or trap and trace devices to record dialing, routing, addressing, and signalling information used in the process of transmitting wire or electronic communications without a search warrant.
Several court cases have raised the question of whether e-mail messages are protected under the stricter provisions of Title I while they were in transient storage en route to their final destination. In United States v. Councilman, a U.S. district court and a three-judge appeals panel ruled they were not, but in 2005, the full United States Court of Appeals for the First Circuit reversed this opinion. Privacy advocates were relieved; they had argued in Amicus curiae briefs that if the ECPA did not protect e-mail in temporary storage, its added protections were meaningless as virtually all electronic mail is stored temporarily in transit at least once and that Congress would have known this in 1986 when the law was passed. (see e.g. RFC 822).
From a rights perspective, the ECPA protects individuals' communications against government surveillance conducted without a court order, from third parties without legitimate authorization to access the messages, and from the carriers of the messages, such as Internet service providers. However it appears to provide little privacy protection to employees with respect to their communications as conducted on the equipment owned by their employer.