http://news.bbc.co.uk/2/hi/technology/7760344.stm

“In a note posted on its support site in late November, Apple said it wanted to ‘encourage’ people to use anti-virus to stay safe online.

“The move is widely seen as a response to the growing trend among cyber criminals of booby-trapping webpages that can catch out Mac users.”

(Dec 2, 2008)