What are the key features of a successful online course? Your response should contain at least 3 placeholders represented by square brackets, such as [course_name]. Highlight at least 2 sections in your answer with markdown, i.e. *highlighted section*. Your answer must contain a title, wrapped in double angular brackets, such as <<Key Features of a Successful Online Course>>. At the end of your response, please explicitly add a postscript starting with P.S.
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