The office computer crisis delayed my commenting on this Washington Post article,
'Delete' Doesn't Mean 'Disappear'. The writer, Rob Pegoraro, does an excellent job explaining the life of e-mail and the techniques for removing e-mail. I suggest anyone and everyone read the technical bits, but I think this passage ought to put the importance of this into perspective for everyone:
So even if both the sender and recipient strive to make a message disappear, "data forensics" companies can dig it up. Brian Karney, the director of product management for one such firm, Guidance Software of Pasadena, Calif., bragged about how easy it is to unearth a long-buried message from the database file created by Microsoft Outlook -- the software used by many businesses and organizations, including the White House.
"Anybody can recover an e-mail," Karney said. "You just need to know how to look and find that stuff."
Encrypting e-mail -- something most users never bother to do -- can keep the contents of your correspondence secret. But it can't hide other data about the e-mail, such as subject, addresses, dates and times, which can be incriminating on their own.
Just because it's possible to find long-lost e-mails doesn't mean anyone is doing that with yours right now.
Your Internet service provider or Web-mail service, if it wants to stay in business, is not likely to eavesdrop.
And your office's IT department may be too busy to bother. Although a lot of companies say they monitor employee e-mail (55 percent, in a 2005 survey by two trade groups, the American Management Association and the ePolicy Institute), you can bet that most rely on automated software to do the job. It takes an exceptionally paranoid, well-financed business to hire people just to read the mail.
If, however, somebody thinks your correspondence in particular hides a sufficiently sordid secret -- especially if that somebody is a politician or a prosecutor -- all that can change.
I added the italics to that last paragraph. I would have also added business competitor to politician or prosecutor.
If you have a business and do not understand why preparing for electronic discovery is necessary for your business, I think reading this article will give you understanding.