Spam, spam, spam, lovely spam

E-mail spam is responsible for 97 per cent of all e-mails and the emission of more than 17 million tons of carbon dioxide. Spam filtering could reduce unwanted spam by 75 per cent, or the equivalent of taking 2.3 million cars off the road.

Around 62 trillion spam e-mails are sent across the world every year, with a return rate of around one in a million, These figures are possible because spammers’ overheads are so low. They steal bandwidth from internet service providers and internet users by hijacking and manipulating a website e-mail form, either directly hacking into a server or using computer viruses to control home computers. This stolen bandwidth is estimated to cost US business over $20bn a year.

Spammers have created “botnets” of millions of zombie computers under external control used to send out spam. The global ratio of infected machines is estimated to be 8.6 per 1,000 uninfected machines, making it hard to identify and block at source. Spammers also tweak the contents of their mail to beat filters. Many contain “word salad” — extracts from online books, for example — to disguise messages.

Internet spam was born just over 30 years ago when Gary Thuerk, a marketer at the now defunct computer firm Digital Equipment Corporation, sent an e-mail to 393 users of Arpanet, the US government-run computer network that eventually became the internet. That first commercial message drew a negative reaction and DEC was reprimanded by Arpanet administrators.

Spam is believed to have got its name from the 1970 Spam sketch from Month Python’s Flying Circus. The sketch is set in a café where nearly every item on the menu includes Spam canned luncheon meat. As the waiter recites the Spam-filled menu, a chorus of Viking patrons sing, “Spam, Spam, Spam, Spam, lovely Spam, wonderful Spam”, hence spamming the waiter’s dialogue with his customers.