How do economists explain why people contribute to Wikipedia? What incentives do contributors have?
I believe they earn no money. And usually, they earn no reputation either, because most of the contributions are anonymous.
I believe this is a public goods game. Have economists studied this &quot;Wikipedia puzzle&quot;? How might they explain it? To what extent would economists consider this a &quot;puzzle&quot;?

By &quot;contributors&quot;, I mean those who edit Wikipedia pages, not those who contribute in other ways (e.g. donations).
I wouldn't underestimate the role of learning by answering.
Drafting a significant text typically forces a person to put their thoughts in order, to engage in research, and then to structure the information for the purpose of recording and conveying it. It is not unusual that further insights or questions emerge during this process, the answerer certainly becomes more familiar with the subject, and good communication is itself a skill that requires significant attention and practice to develop.
Moreover, publicising one's thinking (even to a very small audience) typically invites challenge and puts it to the test of what others think of it, which again tends to flush out all kinds of faults and oversights - either faults in the thinking itself, or faults in the way it has been articulated and formulated into words.
Clearly, the assumption embedded in this question is that communication is done purely for the benefit of the listener, and that knowledge transfer is done in a &quot;jug and mug&quot; style, but there is more truth than you might think in that hoary old claim that academics have much to learn from their students.
So part of the answer to why people freely labour to communicate on sites like Wikipedia (not to mention here at StackExchange) is therefore bound up in the question of what stake they have, not just in developing the knowledge they appear to possess, but also in developing and rehearsing all the broadly intellectual skills associated with the development, retention, and communication of knowledge.