In 2004 at Davos, Bill Gates predicted the death of spam. His prophecy may finally be coming true. Since a peak in 2008, the share of e-mails that are junk has steadily declined. In the past year it has fallen from around 80% to 67% of the global total, according to Kaspersky Lab, a cyber-security firm. Spam filters are doing their job. Sophisticated technology is authenticating senders. Police are cracking down on spammers. And web users are ignoring the spam that gets through. Many spammers have switched to peddling fake handbags and baldness cures via online ads, which are often cheaper and more likely to be clicked on.