Community dynamics at Wikipedia: research done by the PARC - Augmented Social Cognition group

There's an interesting
post about the community dynamics of Wikipedia on the
PARC - Augmented Social Cognition site with several interesting ideas about Wikipedia and the maturation of a website community. This post concludes a four part series by summarizing work presented in a to-be-published paper by Bongwon Suh, Gregorio Convertino, Ed H. Chi, and Peter Pirolli (
link to paper). According to the series, research in the past showed Wikipedia's content and contributions grew at an exponential rate, mirroring the conventional thought that knowledge and web growth would accelerate unbounded. But, around 2006, Wikipedia's contribution rate began to decline. Many now think wikipedia's growth instead follows a logistic growth pattern, with a more bell shaped trend over time.

(from: http://en.wikipedia.org/wiki/Wikipedia:Modelling_Wikipedia%27s_grow...) A logistic trend is likely due to how Wikipedia's increasing mass of content inevitably results in less future content and thus less new-content growth. Some assert the logistic model's eventual limit on content translates to an eventual limit of combined expertise in the Wikipedia community. If we consider content sites which have a smaller pool of contributors but follow a similar growth trend, factors such as limits in site topics or language or geography could similarly limit the community and it's growth. The ASC-PARC group points out how the veteran Wikipedia community has become increasingly resistant to new contributor edits and contributions, resulting in an almost linear increase over time in the veterans undoing edits made by other users (
see the 3rd plot). Certainly this contributes to the decline of new content, but maybe this conservativism in content is also discouraging new would-be contributors from improving Wikipedia. If this is so, could a cultural tendency like this result in stagnation of an entire website? The next post shows that the group which makes 10-99 edits per month (a rate much less than the +1000 edits/month veterans) is a declining population in the Wikipedia community. Since the veteran population is not increasing in size, we assume these users are significantly reducing their contribution rate. In other words, they are leaving the community. The series concludes by drawing an analogy with biological systems that have a limited ecology. Such closed systems give advantage to members which have a competitive dominance over others. In the case of Wikipedia, the ASC-PARC group suggests that due to the increasing limitations to make novel contributions, the wikipedian culture will experience "increased patterns of conflict and dominance". Now I'm wondering if this is a trend we've seen before in other online communities?