America can't control the global flow of ideas

ONE of the quirks of LinkedIn, a career-oriented networking site with over 562m users, is that strangers wish you a happy birthday even when your mum has forgotten. If this happens to you, don't respond: it could be a Chinese spy. According to Reuters, American counter-intelligence chiefs think that China is running a "super-aggressive" campaign on LinkedIn to recruit experts in health care, green energy and technology. Other agencies are nervous, too. The FBI complains of an "unparalleled" leve...