Dr Wu,
I really like the approach of testing different levels of what we understand as 'most of the content' to verify 9-1 ratio of contributors. There seems to be one threat - isn't expected output affecting the research?
From my point of view, the data indicates that if we focus on a single community we can be almost 100% sure there will be a group of contributors and hyper contributors, however the ratio 1-9-90 seems to be questionable. Maybe it is just a concept, not meant to be very accurate, however I am extremely curious if there is no better ratio.
I was wondering if you tried to find more accurate division?
At least just to plot % of posts versus % of users who created them (sorted by number of posts, descending) and find two points having the smallest deviation.
That would give the real insights into tendencies and even if not defining new ratio, that would enable leveling stages of involvement.
Or maybe you did question those levels and it still confirmed 1-9-90 ratio?
Maria