Well, first off, what exactly is a paper town? The term can literally refer to a subdivision that was started but then abandoned, because it was only built on paper with the designs of the subdivision. However, the predominant reference of the term is used in the beginning of the novel when Margo says that Orlando, where they live, is a paper town. This usage of the term describes it as something flimsy and planned. From above, the town seems like it could be made out of paper, with no real depth to it, just a lot of surface that could collapse with one gust of wind. She describes the town as something "not even hard enough to be made of plastic." This demonstrates the superficial type of city Orlando is, especially since she describes it as paper, which literally has absolutely no depth to it. Everything in the town seems to be at a surface level, only concerned with what's on the surface, only focusing on what the eye can see. This concept is crucial to the plot due to the fact that it's because of this superficiality that Margo decides to run away. She's tired of the surface, she's tired of people just assuming that what they see of her is all there is to her, when really there's so much more. She craves that depth and she craves a fresh start in a stronger town, one that's not made of paper.