Mark Zuckerberg may not have the business savvy to propel Facebook's stock to soaring new heights (or even back up to its IPO price), but be that as it may, he ranked No. 1 on Glassdoor's list of the "Highest Rated CEOs" for 2013. The career's site gave Zuckerberg a 99 percent approval rating, but what does that mean? It means his employees...