Megacap growth stocks are making an impact on traditionally blue-chip indexes like the Dow Jones Industrial Average.The Dow Jones Industrial Average includes 30 industry-leading U.S. companies from a variety of sectors. Despite having far fewer components than the S&P 500 or Nasdaq Composite, the Dow remains one of the most widely followed stock market indexes -- acting as a representative democracy, if you will, of the broader market.The composition of the Dow has evolved in lockstep with the U.S. economy. ...