Hi cointoss,
I may have misunderstood your point (apologies in advance if this is the case), but I suspect you're confusing two similar sounding issues . . .
1. For every buyer there is a seller and vice versa
This is true of all markets, but it does not mean that buyers and sellers win or lose in equal amounts. If you buy a stock and it rises and you then sell the stock for a profit, it doesn't follow necessarily that the person who buys it from you makes a loss. They may make a loss if the stock reverses down but, equally, its price could continue to rise and then your buyer - like you - can sell it to someone else for a profit.
2. Your profit is someone else's loss
Ultimately this is also true, in that the profit a trader makes doesn't come out of thin air, it comes from the pockets of other traders, investors and speculators. But, as noted in point one above, it doesn't have to be from the pocket of the person on the other side of your trade. (It's a little different when trading futures, but I won't muddy the waters with that now!) Think of the market as one great big pot of money and, for you to get your hands on some of it, you have to add money of your own to the pot. You then use your skill and judgment to trade with the expectation that you will withdraw more money than you put in.
Liquid validity's point is that most traders fail to achieve this goal, i.e. they end up putting in more money than they take out. And he's right. But this is what attracts people to trading, because the pot is large and if those in the minority are able to trade better than the majority of traders making a loss - even if they're only very slightly better - then they stand to do very well. Very well indeed.
I hope that helps to make things clearer!
Tim.
