The Electronic Messaging Association says no one using e-mail can expect privacy and cautions employees to realize that sending someone an e-mail is "like putting a memo in their out-box."
Except these "memos" are permanent, and so are other computer records at work.
In recent years, e-mails and Internet use have become treasure troves for attorneys hunting for incriminating -- and often embarrassing -- evidence.
A sampling of a few high-profile cases:
1998: A former CIA employee was convicted of possessing child pornography after a network manager detected his work station had called up porn sites on the Internet. He sued, saying the CIA search of his computer was illegal. A judge ruled that the CIA was within its rights to search.
1997: Two black employees sued Morgan Stanley, saying a message sent through the company's e-mail system contained a "vocabulary test" completed by "an 18-year-old ninth-grader" that played on stereotypes of black speech and portrayed blacks as illiterate. The employees said the message created a hostile work environment. (A similar case was filed by two black employees at Citibank). A judge dismissed the Morgan Stanley case, saying a single racist message wasn't enough to show the workplace was hostile.
1997: A California jury convicted a woman of falsifying an e-mail message in order to get a $100,000 settlement in a sexual harassment case against Oracle Corp. The woman said she was fired in 1993 because she refused to have sex with a supervisor, who was her ex-boyfriend. The day after she was fired, she broke into the e-mail system and sent a falsified message to the supervisor from a vice president indicating her termination had been ordered by the vice president "as per your request."
1994: As part of a sex discrimination suit against Microsoft, a judge allowed a female employee to present evidence that her male supervisor referred to himself in e-mails as "president of the Amateur Gynecology Club" and repeatedly circulated sexually oriented messages, including a report on a proposed sex holiday in Finland and a parody on a play called "A Girl's Guide to Condoms."
1993: Nissan Motors Corp. fired two female employees after their supervisor read their e-mails and found messages about their boss in addition to personal messages "of a sexual nature." They sued to get their jobs back, but lost.
1991: After the Rodney King beating by Los Angeles police, Officer Lawrence Powell sent an e-mail to his colleagues on the department's system that ended up haunting him: "Oops, I haven't beaten anyone so bad in a long time."
1990: Epson America fired a group of employees after monitoring their e-mail. The employees filed a class-action suit to get their jobs back, saying the company did not have the right to monitor e-mail. Their case was dismissed in 1991.