They can console themselves with the thought that much of the froth was whipped up by a temporarily under-employed newspaper industry that will move on swiftly to the next target.

ECONOMIST: Don��t mention the war

Twitter's effort to woo small advertisers, begun in December, comes amid investment froth around the start-up.

WSJ: To Grow Big, Twitter Seeks Small Ads

Already, some investors worry that stocks are rising too far too fast, and the BOJ is merely stirring up another round of speculative froth.

WSJ: Japan's Mrs. Watanabe Decides It's Time to Buy Stocks