While everyone is fighting a battle against spam and spammers, a new form of irritation is growing. "Spim" is similar to spam but uses instant messaging services instead of e-mail.

Research firm the Radicati Group says 400 million spim messages were sent last year and this will increase to 1.2 billion by the end of 2004. Alyn Hockey, from internet security firm Clearswift said: "It's not really as dangerous as spam."

Hockey recommends: "Don't accept connections from people you don't know, don't download attachments from people you don 't know; and keep your anti-virus software and operating system up-to-date."