Quote from stockoptionist:
I partially agree with bungrider, chasinfla and others who maintain the liquidity argument. However, I can't help drawing the following analogy to daytraders:
We put out a garage sale one time and there were people out early in the morning driving trucks to load up junk and then turn around and sell it at the local flea markets. Presumably, you can claim that what they do is to take advantage of inefficiencies in the market and hopefully make a buck or two in the process. But I'm still not quite convinced that they are producing anything substantial to society. Daytraders seem to be like them--in a way, taking advantage of micro-inefficiencies while not producing things of substance. Again, I have nothing personal against daytraders, it's just an issue I want to have a clear stand on. And I'm prepared to further change my mind about this.
stock.