A question from Yahoo! Answers:
Should U.S. Social Security be privatized?
Fully privatized? Partly privatized? Not privatized? Why or why not?
Probably not. The vast majority of individuals are very bad at saving and even worse at investing. The U.S. household sector, for example, has a negative savings rate (it spends more than it earns).
For a quick (literally, two and a half minutes) introduction into the problem, watch this video: