Glyn Moody writes: "Apparently, the U.S. Department of Justice has been sending out hoax emails to test the security awareness of its staff. How about applying a similar strategy to tackling spam among ordinary users? If fake spam messages offering all the usual benefits, and employing all the usual tricks, were sent out by national security agencies around the world, it would select precisely the people who tend to respond to spam. The agencies could then contact them from a suitably important-looking government address, warning about what could have happened. Some might become more cautious as a result, others will not. But again, it is precisely the latter who are more likely to respond to further fake spam messages in the future, allowing the process to be repeated as often as necessary. The system would be cheap to run — spam is very efficient — and could use the latest spam as templates."