1. The document discusses the phenomenon of lurking, or passive participation, in online learning communities where some learners never post or post seldom. 2. It notes different estimates for the percentage of lurkers in communities, from the commonly cited 90-9-1 rule to a suggested 55-25-20 ratio from community managers. 3. The document examines possible reasons for lurking such as individual characteristics, situational factors, and the learning environment, and considers whether lurking should be seen as a failure or a legitimate participation strategy.