Second person stories tend to make the reader a character in the book. Second person stories refer to the stories wherein, the reader is directly addressed. This narration is often used by the writers in order to bring the readers closer to the story by characterizing them in the book. When referring to the second person the writer mentions the pronoun "you" in contrary with first-person "I" or third person like he, she, they etc.
Hence, characterizing the reader as the second person in the story helps the reader to reinforce the ideas that drive the story and to give narrator someone to address.