From the June 1999 issue of Startups

Do you watch what you say in your e-mail? Probably not. "Few of us understand [e-mail] can come back to haunt us in court," says Theresa Loscalzo, a partner with Philadelphia law firm Schnader Harrison Segal & Lewis who practices Internet law. "People say things in e-mail they wouldn't otherwise put in writing."

That fact was hammered home when, to undermine testimony given by Microsoft executives during the software giant's antitrust trial, Department of Justice lawyers used piles of Microsoft's in-house e-mails to paint the corporation in a more predatory, less amiable light. It's hard to insist you're a nice, sweet guy when there are folders of e-mails you wrote filled with threats to "cut off the oxygen supply" of competitors.

Think it couldn't happen to you? Don't bet on it. Of course you don't have computer servers that automatically archive e-mail, but most of the big companies you correspond with do, and they typically store all e-mails for six months or longer. Chew on this: "Whenever we litigate, we routinely seek copies of archived e-mail," says Loscalzo, who adds that invariably there are gems to be found when sorting through these cyber mountains.

And that very threat is now fostering entirely new rules for e-mail. Such as? Although the medium seems to encourage off-the-cuff, spontaneous comments, never write an e-mail you wouldn't want published in your hometown newspaper. That means no facile put-downs of competitors, no hasty expressions of anger, no talking about customers behind their backs. And don't say anything you'll regret having forwarded all over the Net, which is often exactly what happens to e-mail. Once an e-mail leaves your hands, it's gone--you have no more control over its distribution. "E-mail needs to be taken as seriously as any other form of business communication," says Loscalzo.

Put bluntly, today's rule for cautious e-mail is this: When in doubt, hold your fire. Don't send that questionable e-mail--if you do, it may just turn up as Exhibit A in court. Loscalzo, for one, has no doubts about that. "We'll be seeing more litigation involving e-mail," she predicts. "You'd think the Microsoft case would have made people more cautious about what they put in e-mail, but I'm not seeing any evidence that's so. People are as careless as ever."

Robert McGarvey started exploring the online world over a decade ago with Genie, and has been writing on--and complaining about--the Net ever since. He writes about the Web for Entrepreneur, BizTravel.com and Upside.