Most of the money "lost" in the stock market was paper profits. If, as many have said, the market was grossly overvalued in the 90s, they weren't even real paper profits, having no reflection in the real world of economic value.

So, basically, the money doesn't "go" anywhere. From one point of view, it never WAS anywhere.

Kids bought Pokemon cards for a few bucks that inflated in price to hundreds of dollars in a few cases. Now they're worth, mostly, a few bucks again. A kid spends five bucks on a card that becomes worth $200, and then drops to six bucks. Did he lose almost $200, or make a dollar? Depends on your point of view, I guess.