Baidu sinks on valuation concerns: "Shares of Baidu.com Inc. plunged more than 20% Wednesday morning as analysts at Goldman Sachs and Piper Jaffray began coverage of the Chinese search firm with 'underperform' ratings due to concerns about its valuation." —MarketWatch

Q: How do you say, "Pop!" in Chinese? A: "Baidu!" I think this justifies a new addition to the Bubble 2.0 Index: BIDU!