You'd better watch out, especially if your e-mail provider is based in Massachusetts, Maine, New Hampshire, or Rhode Island. The First Circuit Court of Appeals has just ruled that your ISP can read your e-mail while it's sitting on their computers, for any reason at all.
Councilman, owner of a website selling rare and out-of-print books, offered book dealer customers e-mail accounts through his site. But unknown to those customers, Councilman installed code that intercepted and copied any e-mail that came to them from his competitor, Amazon.com. Although Councilman did not prevent the mail from reaching recipients, he read thousands of copied messages in order to know what books customers were seeking and gain a commercial advantage over Amazon.
Authorities charged Councilman with violating the Wiretap Act, which governs unauthorized interception of communication. But the court found that because the e-mails were already in the random access memory, or RAM, of the defendant's computer system when he copied them, he did not intercept them while they were in transit over wires and therefore did not violate the Wiretap Act, even though he copied the messages before the intended recipients read them. The court ruled that the messages were in storage rather than transit.
Almost makes me want to run my own server.