"In some types of partner dance, lead and follow are designations for the two dancers comprising a dance couple." "The lead is responsible for guiding the couple and initiating transitions to different dance steps and, in improvised dances, for choosing the dance steps to perform. The lead conveys his choices and direction to the follow through subtle physical and visual signals, thereby allowing the couple to be smoothly coordinated." Wikipedia
Below are links to articles and opinions that discuss social dance leading and following.