My interpretation, having not seen the video (cause I didn't want it to influence my interpretation) is that this is a tongue & cheek song about how there's the "in" crowd that always has to be in hip/fashion and be conformists, then there is the followers who always want to be with the "in" crowd and then there's the others such as the geeks, nerds and the non-conformists. The song is more of a sarcastic/matter-of-fact take on these types of social scenarios, saying "are you in" or are you a geeks/nerd.
My interpretation, having not seen the video (cause I didn't want it to influence my interpretation) is that this is a tongue & cheek song about how there's the "in" crowd that always has to be in hip/fashion and be conformists, then there is the followers who always want to be with the "in" crowd and then there's the others such as the geeks, nerds and the non-conformists. The song is more of a sarcastic/matter-of-fact take on these types of social scenarios, saying "are you in" or are you a geeks/nerd.