There is very little law regarding e-mail right now. The law that exists is state-based, which means that [laws in] each state vary, and even the courts within a particular state may have different ways of handling this issue.

Can employees sue for invasion of privacy? The general rule is that if an employer has a clearly written e-mail policy that says the employee has no expectation of privacy, the employer will probably be safe.

I've had major companies tell me they're more concerned about this issue than they are about [all the other] issues combined.

It's so easy to send information with e-mail.

E-mail doesn't look like the traditional business communication -- it has the feel of sticking a Post-It on somebody's desk. E-mail can be sent without a lot of reflection. Most employees don't really think of the fact that when you send an e-mail there will be a copy on your computer, the network backup tape, etc. It's frequently harder to get rid of an e-mail than a written document.