Indexing is hardly passive

I've mentioned many times in the past the benefits of buying index funds -- you get instant diversification, incredibly low fees and minimize taxes. Most refer to this as passive investing but is it really? I mean you're picking the index instrument (S&P 500, Total Stock Market, Small Cap, International, Fixed Income, etc.) so how is this passive? The truth is you're using passive instruments to implement a strategy to optimize returns. Look here to understand this better: Passive Aggressive