More than ever, investors need total-market exposure to avoid creating a portfolio of losers

"We are increasingly becoming a 'winner take all' economy dominated by a relatively few big players," reports The Wall Street Journal who interviewed Dartmouth engineering and MEM director Geoffrey Parker: "'Networking effects' are driving the winner-take-all economic shift, according to Geoffrey Parker, a professor of engineering at Dartmouth. These effects come into play, Prof. Parker says, whenever a company’s users create value for other users. An illustration is Apple Inc.’s AAPL -0.13% dominance of the smartphone industry: As more people buy iPhones, the more developers want to develop apps for those phones. And the more good iPhone apps there are, the more people want to buy those phones. These networking effects create a 'virtuous cycle' in which one, or perhaps a handful of companies, eventually dominates the competition."