Looks like the IRS believes it can read your emails, Facebook Chats, Twitter Direct Messages, SMS messages, and more without needing to obtain a search warrant beforehand. However, a ruling in the 2010 case, U.S. v. Warshak, by the Sixth Circuit Court of Appeals states that accessing someone's email messages without obtaining a warrant first violates the Fourth Amendment.
According to an IRS 2009 Search Warrant Handbook discovered by the American Civil Liberties Union, the IRS says,
"Emails and other transmissions generally lose their reasonable expectation of privacy and thus their Fourth Amendment protection once they have been sent from an individual's computer."
The ACLU says that under the currently outdated Electronic Communications Privacy Act (ECPA), if an email is in an email provider's server for more than 180 days, or has been opened, it does not require a warrant to access. Authorities can access the emails with just an administrative subpoena. Luckily, the ruling in the U.S v. Warshak protects individuals from unreasonable searches by the government. However, the main fear is whether or not the IRS would be abiding by the Warshak ruling throughout the entire country, or if its only going to be abiding by it throughout the Sixth Circuit.
When the IRS issued edits to its Internal Revenue Manual in March 2011, one year after the Warshak ruling, it still decided to keep its original policy. The manual states that under ECPA,
Investigators can obtain everything in an account except for unopened e-mail or voice mail stored with a provider for 180 days or less using a [relevant-and-material-standard]court order.
Even on today's date, the Internal Revenue Manual retains the same policy that a warrant is not required to search emails stored for more than 180 days. The IRS strongly believes that emails, or any form of communication held in electronic storage, is not protected by the Fourth Amendment. Back in 2009, the IRS Criminal Tax Division's Office of Chief Counsel stated,
"The Fourth Amendment does not protect communications held in electronic storage, such as email messages stored on a server, because internet users do not have a reasonable expectation of privacy in such communications."
The office echoed its stance in 2010 at a presentation, stating, "4th Amendment Does Not Protect Emails Stored on Server." Luckily for us, a lot of companies are all fighting to protect your information and your rights. Amazon, Apple, AT&T, eBay, Google, Intel, Microsoft, Twitter, and many advocacy groups have all asked Congress to update the ECPA to make it clear to the IRS, and other authorities, that they need warrants to access someone's private, electronic conversations.