Someday soon your email will have a receipt for something you didn’t buy. It will be matter of fact and bland but you’re pretty sure your wife would have mentioned it if she had bought, say, a pair of Luis Vuitton sneakers, so the email receipt stands out. You’re paranoid and net-savvy so you know better than to click on a link. You know if you click on a poisoned link you’ll be taken to a bogus page that will try to get your mail password and your credit card number and you’ll wake up in an unfamiliar neighborhood with a headache and a bandage over your right side. But this is odd – there’s...