‘The Electronic Communications Privacy Act of 1986 allows government agencies to in many cases obtain emails older than 180 days without a warrant.
‘That’s why an internal 2009 IRS document claimed that “the government may obtain the contents of electronic communication that has been in storage for more than 180 days” without a warrant.
‘The IRS Criminal Tax Division’s “Search Warrant Handbook,” shows that the division’s general counsel believed “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.”
Probably applies to your online backups, too.
via IRS Thinks It Doesn’t Need A Warrant To Read Your Email.