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We all want to hear from someone, of course, an age-old demand for attention that has spawned everything from cuneiform tablets to SMS-es. And the faster the better. Once a pleasant surprise in the mailbox, electronic messages are beeping in our pockets, at home, play and everywhere in between.

Nine out of ten

Instant gratification, though, comes at a price: an open electronic door that lets in unwanted people as easily as it does friends. In the good old days of deeply felt handwritten letters, the most unpleasant thing would have been a direct marketing package in the post

box. This would be limited by costs for the marketer, of course – whoever mailed it to you had to pay for the package's production and a postage stamp. In an increasingly electronic world, though, you could send an endless series of e-mails circling the world for the price of a P.O. Box.

And that's exactly what's happening – just check your mail. It is estimated that at least nine out of every ten e-mails in your daily inbox will be clogged up by junk e-mail. And it's more than just an irritant that involves deleting them – you're paying for the bandwidth it takes to download them, and throwing yourself open to the viruses they may contain. Legitimate businesses spend billions every year paying for antivirus software that try to identify and screen such incoming communication, a losing battle that gets worse every year.

Biting us back

Wasn't technology supposed to be on our side? Not really, especially in an age where we prize inter-connectivity: from Bluetooth enabled cell phones, wireless broadband networks and public emil accounts. We want to be connected, but the technology that opens the world to us can be used to turn around and bite us in the back. The problem is, it's getting smarter every day.

It wasn't supposed to be this way. Three years ago, Bill Gates, Microsoft's chairman, made an audacious prediction: the problem of junk e-mail, he said, "Will be solved by 2006." And for a time, there were signs that he was going to be proved right. Anti-spam software for companies and individuals became increasingly effective, and many were given hope by USA's federal Can-Spam Act of 2003, which required spammers to allow recipients to opt out of receiving future messages and prescribed prison terms for violators.

Spam 2.0

And then it started getting worse. Because anti-spam software usually looks for keywords to identify junk e-mail, marketers have adapted by hiding behind new techniques like image spam. This is where the words of the advertisement are part of a picture, often fooling traditional spam detectors that look for telltale phrases. Image spam increased fourfold from last year and now represents 25 to 45 per cent of all junk e-mail.

Spammers have used images in their messages for years, in most cases to offer a peek at a pornographic Web site, or to illustrate the effectiveness of their miracle drugs. But as more of their text-based messages started being blocked, spammers searched for new ways and realised that putting their words inside the image could frustrate text filtering. The use of other people's computers to send their own bandwidth-hogging e-mail made the tactic practical. Filtering companies adopted an approach called optical character recognition, which scans the images in an e-mail and tries to recognise any
letters or words. Spammers responded in turn by littering their images with speckles, polka dots and background bouquets of colour, which mean nothing to human eyes but trip up scanners.

Traditional software also looked at where each e-mail was coming from, and if there were multiple e-mails sent from the same source. This has been countered by spammers by conscripting vast networks of computers belonging to users who unknowingly downloaded viruses and other rogue programs. The infected computers begin sending out spam without the knowledge of their owners. Hundreds of thousands of such host computers could be infected every day. Spammers have defied techniques that hoped to identify their digital fingerprints by writing software that automatically changes a few pixels in each image in their junk e-mails.

The sudden appearance of new sources of spam makes it more difficult for companies to rely on blacklists of known junk e-mail distributors. Also, by using other people's computers to scatter their e-mail across the Internet, spammers vastly increase the number of messages they can send out, without having to pay for the data traffic they generate. Because a spammer is using someone else's computer to send out e-mails, his costs are effectively zero, of course, tilting the economics of junk mail in his favour.

A losing battle

While spammers are making money selling fake schemes, stocks and asking for your bank account details, the costs for companies trying to fight spam on their own have tripled, mostly because of increased bandwidth costs to handle bulky image spam and lost employee productivity. And spam is also spreading its wings – once relegated to the world of personal computers, it is now seen through wireless cellphone networks and bluetooth-enabled devices – anything that can connect to you is up for grabs.

There's no question about it – if ninety per cent of all the e-mail sent today is fit for your trash bin, we've already lost the battle. The next phase of anti-spam software will determine if we can re-take our inboxes.