Despite the clamouring hordes calling for 'something to be done', the amount of spam sent whizzing around the Internet is increasing at a rapid rate -- and looks like it will continue to do so for the foreseeable future.

The Internet Industry Association (IIA) has announced that due to "popular demand and a continuing escalation in the spam problem", it is extending its national campaign against spam for a further three months, until August 16.

The initiative is designed to empower end-users by giving them a free trial of antispam tools to allow them to work out the best solution for themselves. An estimated 50 percent of all e-mail is presently categorised as spam, with the percentage steadily growing over the past year, and predicted to grow further.

"Spam is currently impossible to stop at source - spammers use stealth servers and exploit open relays to disguise their origins," said Peter Coroneos, chief executive of the IIA in a statement. "We can start to undermine their efforts by providing end users with the tools to reduce the amount of spam getting into their inboxes."

"There is no doubt that spam is affecting every country and the problem is growing. Without the technological measures currently in place, the utility of email would be seriously compromised," said Coroneos. "E-mail is still the killer application of the internet -- if it goes, the major reason for people staying online will go with it. We cannot afford to let that happen."

Trend Micro, one of the companies offering a free trial of their anti-spam product in the IIA's campaign, is convinced that the only way to effectively stop spam is through heuristic technology, and teamed up with anti-spam company Postini to offer the service. Heuristic technology uses a large number of rules, in this case around 1500, to obtain a probability of a particular e-mail being spam.

"Everyone in a company is affected by spam, not just the IT guys," said Jeani Boots, global product manager of Trend Micro's spam prevention service, explaining why spam was often perceived as a bigger problem than viruses. She said people were getting particularly worried over the increasing amount of hyper-offensive spam, such as those containing images of beastiality, as these presented legal problems in the workplace and moral problems with children at home.

"The one technology that stops the most spam with the least false positives is heuristic technology," said Boots. She claims other solutions, such as whitelists, blacklists, challenge/response scenarios and charging for sending e-mail all had their problems.

Different antispam solutions are better for different people, in the same way that different Web-filtering engines are better for different people. For instance, parents of young children will most likely be best served by a white list system, where appropriate Web domains and e-mail addresses are nominated by the parent, and nothing else gets through. Although this is overly restrictive, it is almost 100 percent effective at keeping out offensive material.

Boots said Trend Micro wanted to "take the lying out of the spamming", and was one of the organisations working with the US Federal Trade Commission to create standards for opt-in and opt-out lists.

Many companies are using their fight against spam as a marketing exercise. Yahoo has instigated a Dump the Junk Day, and is looking for the UK's biggest junk mailer. It is calling on users to "name and shame" their friends and colleagues who bombard them with joke e-mails and 'wacky' attachments.

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