E-mail was not intended as a secure means of communication. Whether you're an attorney, an accountant, a CEO, a chief financial officer or an internal auditor -- even if you work at home or are retired -- you need to know that what you put in an e-mail could one day become key evidence in litigation.

Remember that the vast majority of e-mails traverse the globe in an unencrypted format. This is analogous to sending a postcard via regular mail. Think about it: What's to stop your mail carrier (or anyone else in the postal delivery chain) from reading the messages you write on postcards? Unless you've written in some obscure language used by only a handful of people, nothing can stop such peeping. Yet e-mails (containing information like account numbers, Social Security numbers and/or other sensitive and personal data) are passed around by millions each day with nary a thought to potential consequences.

And e-mails not only are vulnerable to snooping and contribute to a general loss of privacy; they have also become an increasingly used tool in litigation. The use of e-mail information as evidence in the Microsoft antitrust trial was just one of the most visible examples.

According to Jack Seward, a digital forensic accounting technologist in New York, some users still believe that digital encryption of e-mail isn't necessary. They argue that e-mail carries the reasonable expectation of privacy. Although that may have been true once, Seward warns, "known technological vulnerabilities of unencrypted e-mail make this presumption an old wives' tale at best."

What about e-mail accidents? It is easy to have e-mail accidents, and accidents are more common in important business and personal communications than most people may realize. An e-mail message can be easily sent to anyone in an instant -- and there's no hope of retrieving it once you hit Send. It takes just a single errant keystroke or mouse click to send a message to the wrong recipient.