People want to move their net worth into more stable forms, just to ensure that even if the world economy actually does collapse, they will still have something they can trade with. The best forms to hold wealth in under these conditions are forms that will never lose their value: gold and silver bullion coins.
Gold bullion known and the yellow metal, is typically the 'hedge' item in volatile times, but the value of most currencies is so low these days that gold may as well be 'unobtainium'. Most of the gold is being held by large companies and the very rich, leaving precious little for the average person to invest in. But silver bullion is still readily available to you and me at a good price, currently at only 1/70th to the price of gold in 2009.
The interesting thing to note is that, across the Earth, silver is only 1/13th times more common than gold -- which means that Silver is currently grossly under-priced by the market. If and when that market fluctuation corrects itself, people holding these precious metals will find themselves significantly wealthier.
Silver is also used as an industrial commodity, ensuring that it will never entirely lose its value. From the silver paste used in solar cells (sure to be going up in demand due to the rush to create renewable energy resources) to the colloidal silver used in many medicines (also sure to be valuable due to the pressures for universal health care), there is no chance it will ever be entirely out of demand.
Even more importantly, the move to invest in silver bullion coins is only just beginning -- which means if you get 'in' now, you're likely to see your worth increase appreciably simply due to the number of investors that are just starting to consider precious metals as a valid form of investment. Further, as cash continues to decrease in value, bullion coins will become proportionally more valuable.