My investment idea for today is really more of a research note than a stock recommendation. While the investment world is holding its breath during the run-up to the initial public offering of Facebook, the Chinese company Renren (RENN) (tagged with the catchy “Facebook of China” label) came public yesterday. RENN made a nice debut, officially offered at 14, soaring as high as 24 in early trading, then settling down at 19 for most of the day before ticking lower to 18 near the close. Trading action during the stock’s second day pulled it back to 16. The numbers...