Describe the structure and learning system of Seodang, the school system of Joseon, and compare the system of Seodang with the learning system of today's school.

 Seodang was the primary school system of the Joseon dynasty in Korea. It was a community-based system where local schools were established and managed by the community members. The primary focus of the Seodang was Confucianism and children were taught Confucian classics, literature, and Chinese characters.

The learning system of Seodang was based on memorization and repetition, with a strict emphasis on discipline and respect for elders. Students were taught by a single teacher who taught a small group of students, usually from the same family or village.

In comparison, today's school system is much more diverse and formal. Students attend schools that are run by the government or private institutions, and are taught by a trained and licensed teaching staff. The curriculum is much broader and includes subjects such as mathematics, science, history, and languages. The teaching methods have also evolved to include more interactive and student-centered approaches such as project-based learning and group work.

Overall, the differences between Seodang and today's school system are marked by changes in society, economy, and technology, leading to differences in education policies, pedagogy, and curriculum.