Tricky mathematical puzzles like Sudoku could be the next weapon in the fight against spam, an Australian computer scientist suggests.Paul Gardner-Stephen from Flinders University in Adelaide is looking for ways to improve existing spam filters, which try to prevent unwanted email from getting to your inbox.”The trouble is that they’re not entirely accurate, so you still get some spam in your inbox and some real mail gets bounced,” he says.
http://abc.net.au/news/stories/2007/11/19/2095186.htm