Complex sentence: Many have speculated on what the song means; many have found that "Are you In" can refer to whatever the listener wants it to mean, although in the case of the video, it refers to a swingers club.
Split into simpler sentences: Many have speculated on what the song means, many have found that "Are you In" can refer to whatever the listener want's it to mean. In the case of the video it refers to a swingers club.