By Darren Waters
Technology editor, BBC News website
Many big companies are harbouring hijacked PCs that send out spam
Spam continues to blight e-mail exactly 15 years after the term was first coined and almost 30 years since the first spam message was sent.
The term is thought to have been coined by Joel Furr, an administrator on the net discussion system Usenet, to refer to unsolicited bulk messages.
More than 90% of all e-mail is spam, according to anti-spam body Spamhaus.
"Spam is a real life arms race," said Mark Sunner, chief analyst at online security firm Message Labs.
Billions of spam e-mails are sent each day, blocking mail servers, slowing down networks, infecting people's computers with viruses, helping hijack machines and generally making the internet a painful experience for many.
Mr Furr told BBC News that the anniversary of his first use of the term was no cause for celebration.
"I prefer commiseration," he said.
Mr Furr first used the term to refer to bulk postings on discussion boards on the internet but in the years to come spam became associated with e-mail.
"But even today there are many discussion groups that are unusable because of the amount of spamming," he said.
Richard Cox, chief information officer of anti-spam body Spamhaus, said: "Spam means there is an increasing risk to e-mail; it cannot become a reliable vehicle for getting messages across."
Mr Furr said: "In recorded human history as communcation barriers drop and as communication becomes easier civilisation progresses.
"We have this awesome tool to make it possible for people in any part of the planet to exchange ideas with one another and yet people are going out of their way to not use it because of the spammers, because of the jerks.
"It's holding back innovation."
"When e-mail was designed the internet was largely used by people you could trust," said Mr Cox.
"Unfortunately not only did bad people start to use the internet, the gates to the internet were transferred from fairly prudent technologists to people who wanted to make money out of it.
"That's when spam caught on and ever since it has been a rear-guard action."
The term spam was inspired by the Monty Python sketch, first shown in 1970, in which a restaurant only serves the processed meat product.
In the sketch, a group of Vikings start singing: "Spam, lovely spam, wonderful spam."
The term was picked up in internet chat rooms in the early 1970s and used in a variety of contexts until it became best-known as a reference to unsolicited bulk e-mail, according to research carried out by Brad Templeton, who is chairman of the board at the Electronic Frontier Foundation.
The first unsolicited bulk e-mail was sent by a marketing representative at computer firm Dec on 3 May 1978, when he e-mailed every West Coast user on the Arpanet, the original building block of the internet.
The e-mail was inviting users to attend an open day in which the firm would be showing off its latest range of computers.
Mr Cox said years had been taken up trying to persuade government to ban spam.
"The Chinese and Russians are a major problem and probably always will be," he said.
Mr Cox said the two countries' governments were apathetic about dealing with spam because although it originates in their countries, its effect is felt largely outside their borders.
According to the Spamhaus Project, about 200 spammers worldwide are responsible for about 80% of all spam.
Much of spam is sent from ordinary household computers that have been hijacked by hackers, and turned into what is known as botnets, which automatically spew out messages. Mark Sunner said spam was a problem that was constantly evolving.
"The bad guys are at least as technically proficient as the security services trying to stop them."
He added: "The bad guys at the sharp end are using these botnets to do some really clever stuff."
In the past, botnets could be taken down by finding the central server controlling the machines. But the latest variants of botnets are using a technique called fast-flux domain name service which shifts the location of servers every three minutes.
"There are still a number of spam factories in the US which are bulk sending spam," said Mr Cox.
Spamhaus maintains a register of known spammers and spam gangs, many of whom are based in China and Russia.
The body also maintains a list of internet service providers that are failing to deal with computers that have been hijacked.
Mr Cox said UK service providers like BT, Bulldog, Wanadoo and Tiscali were failing to tackle the problem of botnets.
"There has been minimal activity by many internet service providers, all of whom are blaming the dubious legal situation of spam," he said.
Mr Cox said the battle against spam was being scuppered due to lack of government and law enforcement co-operation across borders.
"The spam may come from Bulgaria but if its controlled by somebody in Russia and paid for by someone in the US - who do you prosecute, and in which country?
"How do you get the evidence into the right country? We're building on this but it's a very slow process."
Mr Cox said it was unlikely spam would ever be defeated completely.
"I don't think it's realistic to believe we will never receive spam," he said.