As an investment, gold (or gold certificates) have a property that offsets its high volatility and low long-run returns. It might be negatively correlated with the stock market, such that it “zigs” when the stock market “zags”. In the technical parlance it may have a negative beta. (The paper below attacks this hypothesis, but it at least finds that gold is a near-zero beta asset.)
For those interested in investing in gold… I’d recommend other investments. But if you’re really really adamant, you should at least read about its properties from someone other than a salesman or political commentator, right? Here’s a link: !PDF! : deepblue.lib.umich.edu/bitstream/2027.42/63919/1/fei_fan_2009.pdf
The author characterizes gold as just another foreign currency, albeit one that doesn’t pay interest.