From the article:
In a landmark decision issued today in the criminal appeal of U.S. v. Warshak, the Sixth Circuit Court of Appeals has ruled that the government must have a search warrant before it can secretly seize and search emails stored by email service providers. Closely tracking arguments made by EFF in its amicus brief, the court found that email users have the same reasonable expectation of privacy in their stored email as they do in their phone calls and postal mail.
This is pretty huge. Especially with all the recent news of ISPs being forced by the gov't to crack open their subscribers' data...
Source -> http://www.eff.org/deeplinks/2010/12/breaking-news-eff-victory-appeals-court-holds