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The Hofmeister kink is a small design feature of BMWs.  It is the name for the small cutout of the rear side windows on the C-pillar of the car. Rather than having the rear side window extend all the way down as might be expected, it angles back toward the front of the car. It is named after the legendary Director of Design at BMW, Wilhelm Hofmeister. It first appeared on the 1961 BMW 1500. You can see this on the 1500 in the image below.  (Circled in blue)

The Hofmeister kink has become a signature design element of all BMWs.  BMW claims that it "subtly highlights" that the cars are rear-wheel drive.  Since it first appeared, the kink has appeared on every BMW manufactured. Below is the C-Pillar of all of the BMW "Compact Exec" type cars since the 1500. (The modern model is the 3-Series)

During that time BMW has become synonomous with quality; the 3-Series is a legend and has been named to the Car and Driver Ten Best list every year since 1992.  As expected, the Hofmeister kink is now appearing on all kinds of cars.  My hypothesis was that it would appear most on cars that were meant to seem luxurious, or high-end.  Naturally, it wouldn't appear on a Mercedes, being rivals with BMW and I would be surprised to see it on any car or make with a strong design history.