Economic Bubbles, Bubbles Everywhere. Which Will Last?

NYTIMES/
"Bubbles are episodes of collective human madness — euphoria over investments whose skyrocketing values are unsustainable.
They tend to arise from perceptions of pending shortages (as happened last year, with the oil bubble); from glamorized new technologies or investment frontiers (like the dot-com bubble of the 1990s, the radio bubble of the 1920s or the multiple railroad bubbles of the 19th century); or from faddish cultural obsessions (like the Dutch tulip bubble of the 17th century, or the more recent Beanie Babies bubble).
Often they are based on legitimate expectations of high growth that are “extrapolated into the stratosphere,” as the economist Daniel Yergin, chairman of IHS-Cambridge Energy Research Associates, put it. Such is the fear over investment in emerging markets like China."