While it's unlikely the e-mails most people fire off will leave them staring down the barrel of a 10-year prison sentence, the e-mail is the information age's two-edged sword.

Ctrl+Enter: Send to jail

Quick, cheap and seemingly private, e-mails have the ability to offend, infuriate and upset out of all proportion to their innocuous appearance.

As anyone who has been "flamed", "spammed", or like actress Kate Winslet, "stalked" via e-mail will attest, the "You've got mail" message is no longer the pleasant novelty it once was.

Likewise, who hasn't pored over the contents of their "Sent Items" file, double-checking what they have written and who to?

"I'd got an e-mail from this weird bloke at work, and decided to send it on to a couple of my friends," says one anonymous office worker.

Return to sender

Having added his own withering assessment of its contents, he sent on the message... or so he thought.

"It dawned on me afterwards that, no, I hadn't hit 'forward'. I had hit 'reply'. My message was just sitting there in his inbox, like a ticking timebomb, waiting for him to log on."

Fortunately a friendly techie retrieved the offending item. "It always pays to stay on the right side of techies."

"Doh!": Be careful what you send via e-mail

Employees at Asda, NatWest Markets and Norwich Union have all got into hot water over ill-advised electronic messages.

Dr David Lewis, author of Information Overload - Practical Strategies for Survival in the Modern Workplace, warns against letting emotions impinge on your e-mails.

"Never send an e-mail when you're angry or upset. You will regret it or should regret it."

Flame throwers

Mr Lewis also chides bosses who wield "flame" e-mails "as weapons of political in-fighting".

"E-mails should never be used to discipline staff. If they are, they should be sent directly, not copied to the entire office as a form of public humiliation."

So why can e-mails wreak such havoc?

"They deny us any other information. Over the phone you can pick up clues from voice tone, the speed of speech and accent. These act as a subtext to the conversation."

A face-to-face clears the air

A study at America's Northwestern University found business negotiations conducted electronically ran into more difficulties than those which began with a getting-to-know-you phone chat.

For tricky topics, you can't beat a face-to-face meeting.

"It's been found 60 to70% of the information people pick up during conversations comes from the face and posture of the person they're talking to."

Watch words

The fact they can be dashed off in seconds is often seen as the great advantage of e-mail, but less is not necessarily more, say Mr Lewis.

"Language is ambiguous. It's always best to add a few extra words to your e-mail that make the meaning more clear."

To: Teacher@school Subject: Home time

Language expert Dr Joan Beal says our e-mails not only endanger office relations, they may jeopardise English as we know it.

"The extent to which formal English will cease to exist depends on how much e-mail catches on. It's very difficult to predict."

Ms Beal says as written forms of communication, e-mails are marked by their informality.

"They're a halfway house between speaking and writing. People are less cautious with language and content in their e-mails."

R U mssng out lttrs?

Rather than the conventional structure most of us use in letters, e-mails are often "telegraphic" in style - taking liberties with grammar usually only witnessed in cellphone "txt" messages and Prince song titles.

"People miss out words, ignore typing errors and rarely run their e-mails through the spell checker."

R U chnging how U rite?

With more than half of 9 to 12-year-olds in a recent BT poll saying they expect e-mail to replace the telephone and the letter, formal English could face an uphill struggle.

Of course, we may see the light and reform our e-mailing ways. The anonymous worker who sent out a potentially career-terminating message tried to turn over a new leaf.

"I promised myself never to abuse e-mail again. I haven't kept the promise."