Electronic Communications Privacy Act of 1986

A good source for all things related to privacy is https://epic.org.
EPIC stands for Electronic Privacy Information Center.  It's a great resource, as is the Electronic Frontier Foundation at https://www.eff.org/ -- both are added to the links on the right side of the blog.

Recently, the hot news is that the House Judiciary Committee has voted 28-0 in favor of the Email Privacy Act, H.R. 699, a bill that would establish a warrant requirement for the disclosure of all electronic communications. The law would also require notice to customers whose communications have been collected. With 314 members of the House cosponsoring, the bill is slated to be considered by the House on April 25th. Senator Leahy, who has sponsored an identical bill in the Senate, said that "Congress has waited far too long to enact these reforms."

To understand the importance of all the news related to domestic "snooping" on devices and apps without informed consent, you have to first understand ECPA.  According to the Epic site:

The Electronic Communications Privacy Act ("ECPA") was passed in 1986 to expand and revise federal wiretapping and electronic eavesdropping provisions. It was envisioned to create "a fair balance between the privacy expectations of citizens and the legitimate needs of law enforcement." Congress also sought to support the creation of new technologies by assuring consumers that their personal information would remain safe.

ECPA includes the Wiretap Act, the Stored Communications Act, and the Pen-Register Act. Wire communication refers to "any aural transfer made in whole or in part through the use of facilities for the transmission of communications by the aid of wire, cable, or other like connection"; in short, it refers to phone conversations. An oral communication is "any oral communication uttered by a person exhibiting an expectation that such communication is not subject to interception under circumstances justifying such expectation"; this constitutes any oral conversation in person where there is the expectation no third party is listening

 You can read more about ECPA, and pay close attention to the section on Disclosure of Records as well as reasons for Reform.  At the top of the page, you can access recent news on this topic.

Feel free to add what you know.  The new bill being considered now in the House and Senate is intended to close the loop on disclosure and informed consent, but Epic and others think it hasn't gone far enough.