And how do these guys turn your home computer into a bot in the first place? They send out an innocuous-looking email that actually has a trojan attached. When you load the attachment, it installs itself, and, bingo: your computer is under their control.

So Symantec thinks this is enough of a problem these days that it requires its own form of defence, hence Norton Antibot. This is a new program that sits on the computer all the time, and steps in whenever anything is run. It's designed to make sure the new programs are all clean. Unlike virus scanners, which only check programs' behaviour when asked, Symantec tells us that Antibot will constantly check all running programs.

Symantec says that the reason it wasn't included in the company's other existing security products is that they're already under development, that bots are enough of a threat that users should be protected now, and that it would have taken too long to integrate Antibot into the other software.

It's certainly an interesting area of security, and we'll be examining Antibot in detail over the next few weeks to see if it lives up to the claims. Keep an eye on Computeractive.co.uk for the review.