Start with the non-geeks:
In other work, Berger examined the 2004 yellow wristband phenomenon. A research team at Stanford first sold the bands to students living in one dorm. A week later, researchers began selling the wristbands in a neighboring dorm with a stronger academic focus and a social reputation as a "geek" dorm. A week after the wristbands were adopted by the "geeks," there was a 32% drop in students wearing the bands at the first dorm. The idea is "that people in the original dorm abandoned the wristband to avoid other students thinking they were similar to the geeks," Berger says.
(Hat tip: cktutors.)