The document analyzes trends in Wikipedia contributions and editor populations that suggest its growth is slowing. Exponential growth models no longer apply as activity levels, new edits, and editor numbers approach carrying capacities. Occasional editors face more reversions as resistance grows. Editor classes contribute differently over time, with the middle class producing a smaller proportion of edits. The population dynamics follow a logistic model of ecological limits replacing the preferential attachment of initial growth. Factors like coordination costs, available content, and tools affect Wikipedia's changing growth patterns.

1. Slowing Growth of Wikipedia:Implications for the Future Bongwon Suh, Gregorio Convertino, Ed H. Chi, Peter Pirolli Augmented Social Cognition Area Palo Alto Research Center

2. What’s Happening to Contribution Patterns inside Wikipedia? What’re the Global Activity level patterns? What’re activity patterns by Editor Classes? Are the Population Sizes stable? Analysis of Population by Editor Class

3. Exponential Growth of Wikipedia was an accepted ‘fact’ Number of Articles (Log Scale) http://en.wikipedia.org/wiki/Wikipedia:Modelling_Wikipedia’s_growth

4. Growth of Edits Monthly Edits

5. Growth of Active Editors Active Editors

6. Something happened in early 2007 Monthly Edits

7. Slowing Growth in Global Activity Monthly Active Editors *In thousands

8. What’s Happening to Contribution Patterns inside Wikipedia? What’re the Global Activity level patterns? What’re activity patterns by Editor Classes? Are the Population Sizes stable? Analysis of Population by Editor Class

9. Activity By Editor Classes Monthly Edits by Editor Class (in thousands)

10. Monthly % of Edits by Editor Class

11. Reverts in Wikipedia Undoing the effects of one or more edits The page being restored to a version that existed sometime previously. Reverting may also refer to any action that reverses the actions of other editors. Fighting vandalism This analysis exclude vandalism to model “resistance”

12. Ratio of Reverted Contributions Monthly Ratio of Reverted Edits

13. Growing Resistance Increased resistance from the Wikipedia community to activities by occasional editors Disparity of treatment of edits Occasional editors have been reverted in a higher rate Photo: http://lianza2009.wordpress.com/

14. What’s Happening to Contribution Patterns inside Wikipedia? What’re the Global Activity level patterns? What’re activity patterns by Editor Classes? Are the Population Sizes stable? Analysis of Population by Editor Class

15. Population Analysis Monthly Active Editors

16. Population by Editor Class

17. Some Key Takeaways What’re the Global Activity level patterns? No longer following an exponential growth curve. Logistic growth is now a better explanation What’re activity patterns by Editor Classes? Middle class decreasing their proportion of edits Different editor classes experience differing resistances Are the Population Sizes stable? Middle class a smaller portion of the pyramid

18. Exponential Growth Model Exponential growth model Growth rate depends on the current N Preferential Attachment: Edits beget edits The more number of previous edits, the more number of new edits r, growth rate of the population

19. Logistic Growth Model Ecological population growth model r, growth rate of the population K, carrying capacity (due to resource limitation)

20. Number of New Articles Follows a logistic growth curve New Article

21. A modified logistic model Carrying Capacity as a function of time.

22. Struggle for Existence - Darwin Biological system Competition increases as population hit the limits of the ecology Advantage go to members of the population that have competitive dominance over others Analogy Limited opportunities to make novel contributions Increased patterns of conflict and dominance

23. Population Dynamics Model Ecological growth model r, growth rate of the population K, carrying capacity (due to resource limitation) r-Strategist Growth or exploitation Less-crowded niches / produce many offspring K-Strategist Conservation Strong competitors in crowded niches / invest more heavily in fewer offspring [Gunderson & Holling 2001]

24. Factors Affecting the Growth of Wikipedia People-ware Growing resistance to new content Coordination cost and bureaucracy Knowledge-ware Availability of easy topics to write about Tool-ware Quality of tools used by editors and admins

25. Thank you! Monthly Ratio of Reverted Edits ed.chi@parc.com http://asc-parc.blogspot.com Augmented Social Cognition Area Palo Alto Research Center

26. http://strategy.wikipedia.org

27. User-Block and Vandalism

28. Page-Protection and Vandalism