Conflict in Divergent arises because the character is, as the title might imply, different; she fails to fit into a single "faction," a group determined by your strengths--selflessness, honesty, intelligence, kindness, or bravery. The story itself isn't an unusual one for YA lit: main character faces romantic subplot plus conflict with a corrupt government that threatens her life. And there's another thing: the prevalence of sorting. Think about popular YA novels/series of our time--Harry Potter, the Hunger Games, the Giver, Percy Jackson and the Olympians--and then think about how sorting plays a role. Hogwarts houses in HP. Districts in HG. Assigned roles (Birthmother, Giver, etc.) in The Giver. Houses based on parentage in Olympians.
After watching Divergent I wondered why. Why do we rely so much on sorting in YA lit? Is it because in real life, characterization of teenagers and kids happens more by the groups we express allegiance to than the values we ourselves espouse? Because people don't think that our morality has emerged beyond Kohlberg's conventional level of moral development, and thus we need our group loyalties to keep us in line?
Or is it something else entirely, a shrewd way for writers to tap into the innate desire of so many youngsters, who are struggling with finding their own groups, to simply belong? In other words, a rather terrifying question: do all these dystopian (or simply fantasy, in the case of Harry Potter or Olympians) sorting mechanisms speak to something we actually desire?