The one finding I found of particular interest: 32.95% noted they would be more likely to contribute if "It was clear to me that other people would benefit from my efforts". This leads me to a puzzle I've wondered about: is have someone tweak/add to your contribution -- rather than delete it -- a sign of being of use, or of being incompetent, as claimed by one of the earlier studies of Wikipedia motivation (Zhang and Zhu, 2006). Z&Z claimed "adding new content to an article decreases article creator's incentive more than deleting content" in accordance with the "perceived competence" theory: if someone changes something that you did you feel incompetent. Intuitively, I always found this odd as I'd think additions to one's new article is indication that people found it useful in some way. However,two things I never understood about Z&Z are: (a) "we expect our contribution to decrease over time" and (b) "excluding interaction variables" in models (5/6) give them opposite effects. How do they account for a natural decline in article creation, I don't know what the interaction variables are, did they mean independent variables?