The BBC reported today that millions of computers throughout the world had been infected by viruses that, for example, send out spam to other computers. Here’s another link. In the first chapter of the book I described a survey by the security company McAfee that reported that in 2009 this was a major problem. The survey that McAfee carried out referred to an infected computer as a zombie. The report by the BBC describes a long term study that showed that the problem is increasing; it describes an infected computer as a bot and a collection of computers as a botnet. Although the UK came off pretty well in terms of infected computers the figures are still really scary. There is some excellent advice from Microsoft about infections and botnets here.