Your employer and the government can snoop legally.
We use e-mail for everything from business negotiations to quick I-love-yous. Because e-mail resembles a telephone conversation, we too often assume it's private.
It's not. Just ask Sarah Palin. A college student recently broke into her Yahoo e-mail account with frightening ease; he boasted that it took just 45 minutes using Wikipedia and Google to find the answers to Yahoo's security questions about her birth date, ZIP Code, and where she met her husband.
But break-ins are hardly the only threat to our e-mail privacy.
Who can see your e-mail – even en route – is a complicated question, made more uncertain by a recent court decision.
First, your office e-mail is governed by whatever rules your company decides. For example, Harvard University, where I work, states that e-mail "may be accessed at any time by management or by other authorized personnel for any business purpose." Businesses need to be able to investigate fraud, but such sweeping authorizations create opportunities for abuse.
What about government searches? Let's start with the easy case. If you go to China and e-mail or instant message from your hotel room, the Chinese government may read your content. It's scanned for "security" purposes – the government is looking for discussions of Tibetan independence, perhaps. You may never notice anything, or you may mysteriously lose your Internet connection. It recently came out that China monitors and censors text messages among Skype users – a Canadian research group uncovered more than 166,000 censored messages.