Consumer behavior doesn’t really make right-angle turns. It evolves slowly over time, and moves like a wave through trendsetters to fast followers through to laggards. But the accumulation of changes over time often leads to inflection points where the sum of the changes feels like a right-angle shift, even though the signs of that change were really there all along. When you strip away all of the evolutionary changes, you can break down behavior shifts into the big rocks thrown into the water, and then all of the ripples from those rocks as the impact spreads through consumers. Hindsight, of course, also helps tremendously. In that light, there have really only been two major shifts so far in consumer behavior that have fundamentally changed the retailing game since the rise of internet shopping. Read more at Forbes.