Back in 1986, the Electronic Communication Privacy Act (ECPA) was passed, which stated any emails older than six months were considered abandoned and eligble to be seized by authorities without a warrant. The reasoning at the time was because emails would be deleted after being read, since cloud servers and large amounts of network storage weren't being considered. However that isn't the case now, as emails can be kept on a server indefinitely due to 10GB or more of storage capacity on the likes of Gmail. The good news is the US Congress has taken notice, as tomorrow the Senate Judiciary Committee plans to meet to "mark up" a reform for the ECPA. The House Judiciary Committee held a meeting on it last month, but both are working to ensure a warrant is needed for much more than just emails.
Senators Patrick Leahy (D-VT), chairman of the Judiciary Committee, and Mike Lee (R-UT) proposed the new bill, dubbed the Leahy-Lee bill, which "would require a warrant for all private electronic content. So it's e-mails, it's texts, Google Docs, it's photos in Picasa, it's private social networking posts." Google Docs and other non-communcations require a subpoena to be accessed. The senators want everything protected by the Fourth Amendment, both for the privacy of US citizens and companies with cloud services. The ACLU supports the bill and hopes it can pass the Senate Judiciary Committee with a voice vote.
The US House of Representatives is also considering email privacy, as well as location tracking. A separate hearing tomorrow by the Senate Judiciary Committee plans to address location tracking, with senators Ron Wyden (D-OR) and Ron Kirk (R-IL) proposing that one. It isn't known if the Senate would incorporate both bills into one or address each separately, but the fact Congress is looking into it can only be seen as positive.
Source: Ars Technica