We don't have enough information to know exactly who Karen is. She could be an ordinary person, a student, a teacher, or just someone who likes to read stories.
Given only 'dateline karen read story', Karen's identity remains a mystery. She might be a staff member at Dateline who was reading a story for work purposes. Or she could be a person who was interviewed by Dateline and was reading a story during the interview, or she could be an ordinary person whose story - reading experience is being highlighted in relation to Dateline.
There are many good stories in Cleveland, Ohio. For example, the city has a rich sports history. The Cleveland Cavaliers' championship win was a great story of perseverance and teamwork. It brought the whole city together, with fans cheering in the streets.