Fantastic intorduction on ETF

Finally I've found a solid introduction on ETF Although I don't agree that passive managed fund can be better performed than active one, simply because they are not efficient portfolio in theory, ETF is quite popular. I think the key fact is that the ETF's nature of hedging and speculating increases the rate of liqiudation, thus makes it easier to raise fund than other strictly passive managed mutual fund. Normally ETF will adjust its portfolio structure every half year. If we reduce that interval, it more and more resembles active managed funds.