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1. When graphics improve liking but not learning from online lessons

2. Field experiments of success-breeds-success dynamics

3. Threading is Sticky: How Threaded Conversations Promote Comment System User Retention

4. Wikipedia Bibliography:

   1. Commitment device

   2. Randomized controlled trial

   3. Behavioral economics

   4. https://en.wikipedia.org/wiki/Massive_open_online_course

      https://en.wikipedia.org/wiki/Massive_open_online_course