For the folks that think they understand stock prices, you should really read "The Little Book that Beats the Market". Pretty interest stuff.

There is no rhyme or reason why stock prices fluctuate so much in 99.9% of the companies out there. Buying stock is legalized gambling, the ONLY thing holding up the house of cards is that others are willing to go along with the idea. You're not buying a piece of the company, you're buying a piece of paper, and that's generally not even the case anymore. You can't go to the company that you just bought a share from and trade in your stock for money, and you certainly don't get an equal share of their profits at the end of the day (and don't point out dividends, paying $80/share for some oil stock and getting $0.50 in dividends from it is hardly cost effective)...

People that play the stock market are betting on appreciation, just like home owners do. But at least homes on tangible.