The Federal Reserve wants to know what the internet is worth to you. The answer could help the central bank solve one of the most puzzling paradoxes of the modern economy: The current expansion is the longest in history, yet productivity gains are weak and GDP growth, while steady, is far from stellar. In a speech this week, Fed Chairman Jerome Powell raised the possibility that the problem is with the data itself. GDP measures the value of products and services that are bought and sold. But many of the greatest technological innovations of the internet age are free. Search engines, e-mail, GPS, even Facebook — the ... (full story)