Why is "Monetary policy credibility" trending?

Wikipedia Overview

Monetary policy is the policy adopted by the monetary authority of a nation to affect monetary and other financial conditions to accomplish broader objectives like high employment and price stability. Further purposes of a monetary policy may be to contribute to economic stability or to maintain predictable exchange rates with other currencies. Today most central banks in developed countries conduct their monetary policy within an inflation targeting framework, whereas the monetary policies of most developing countries' central banks target some kind of a fixed exchange rate system. A third monetary policy strategy, targeting the money supply, was widely followed during the 1980s, but has diminished in popularity since then, though it is still the official strategy in a number of emerging economies.