A question from Yahoo! Answers:

Difference btw stock market and gambling??

well, first of all, I dont know wat a stockmarket is(dont call me dumb) i tried to search in dictionary .com but don’t understand it. and please, tell me some differences.

The difference is that gambling is a zero-sum game (one player’s gain is another player’s loss; players taken together as a group do not win or lose). This is, of course, assuming that there is no house take; if there is, the game becomes a negative-sum game (players as a group lose whatever happens).

Stock market, in contrast, is a positive-sum game (in the long run, players as a group win about 12% per annum in nominal terms).