slowing growth of wikipedia and models of its dynamic (presented at wikimedia foundataion and...

The Singularity is Not Near:Slowing Growth of Wikipedia

Bongwon Suh,

Gregorio Convertino, Ed H. Chi, Peter Pirolli

Augmented Social Cognition Area

Palo Alto Research Center

Exponential Growth of Wikipedia

Number of Articles (Log Scale)

http://en.wikipedia.org/wiki/Wikipedia:Modelling_Wikipedia’s_growth

Active Editors

Growth of Monthly Edits

Monthly Edits

Something happened in early 2007

Monthly Edits

Slowing Growth in Global Activity

Monthly Active Editors

So What Happened?

No major incident reported– Wikipedia temporarily blocks the entire

nation of Qatar by mistake– Microsoft offers cash for Wikipedia edit– “Essjay” controversy

Characterizing the evolution of contribution patterns inside Wikipedia– Data-driven approach

http://www.flickr.com/photos/lightpaintbrush/3747649160/

Slowing Growth of Wikipedia

1. Global Activity– No longer following an exponential growth curve

– Which model can explain the slowing growth?

2. Activity Patterns by Editor Classes

3. Analysis of Population by Editor Class

Global Activity of Wikipedia

Edit Activity

Active Editor

Earlier Exponential Growth Model

Number of Articles

Log Scale Linear Scale

Earlier Exponential Growth Model

Edits beget edits– more number of previous edits, more number of new edits

€

N(t) = N0 ⋅ert

€

dN

dt= r ⋅N

Growth rate of population

Currentpopulation

Growth rate depends on current population Nr = growth rate of the population

Logistic Growth Model

Ecological population growth model– r, growth rate of the population– K, carrying capacity (due to resource limitation)

€

dN

dt= r ⋅N ⋅(1−

N

K)

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 20100

500000

1000000

1500000

2000000

2500000

3000000

3500000

4000000

Year

Po

pu

lati

on

K

http://en.wikipedia.org/wiki/Wikipedia:Modelling_Wikipedia’s_growth

Number of New Articles

Follows a logistic growth curve

New Article

A Modified Logistic Model Carrying Capacity as a function of time.

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010

Year

Po

pu

lati

on

K(t)

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


1. Global Activity– No longer following an exponential growth curve

– Which model can explain the slowing growth?

2. Activity Patterns by Editor Classes



1. Global Activity– No longer following an exponential growth curve.

– Logistic growth is now a better explanation

2. Activity Patterns by Editor Classes– Patterns of conflict and dominance?


Defining Editor Classes

Highly skewed contribution pattern– Top 3% users contribute 50%+ edits– A lot of single-edit users

Five Editor Classes– Monthly edit count– No bot, vandalism included in the analysis– 1000+: editors who made more than 1000 edits in that month– 100-999– 10-99– 2-9– 1

Activity By Editor ClassesMonthly Edits by Editor Class (in thousands)

Monthly % of Edits by Editor Class

Revert as a measure of resistance

Revert: Undoing one or more edits– The page being restored to a version that

existed sometime previously. – Often used to fight vandalism

Revert ratio as resistance metric– # of reverted edits / # of total edit– This analysis excludes vandalism to

model “resistance”

Ratio of Reverted Contribution

Monthly Ratio of Reverted Edits

A take away: Growing Resistance

Two interpretations:– Overall increased resistance

from the Wikipedia community to changing content

– Disparity of treatment of edits» Occasional editors have been

reverted in a higher rate

Example of increased patterns of conflict and dominance

Photo: http://www.flickr.com/photos/efan78/3619921561/


1. Global Activity– No longer following an exponential growth curve.– Logistic growth is now a better explanation

2. Activity Patterns by Editor Classes– Patterns of conflict and dominance?




2. Activity Patterns by Editor Classes– Yes. We see patterns of conflict and dominance

– Different editor classes experience differing resistances




2. Activity Patterns by Editor Classes– Patterns of conflict and dominance

– Different editor classes experience differing resistances

3. Analysis of Population by Editor Class– Are the population stable?

Population AnalysisMonthly Active Editors * Log scale

Population by Editor Class



2. Activity Patterns by Editor Classes– Patterns of conflict and dominance– Different editor classes experience differing resistances

3. Analysis of Population by Editor Class– Are the population stable?



2. Activity Patterns by Editor Classes– Patterns of conflict and dominance– Different editor classes experience differing resistances

3. Analysis of Population by Editor Class– Middle class a smaller portion of the pyramid

It depends…

So… Is It Bad?

http://alfalfamedia.com/wp-content/uploads/2009/02/content-is-king.jpghttp://www.collegesofdistinction.com/collegetemplates/images/2386/community.jpg

If what you care is sustainability of the community…

Community is King– Sustainability of a system– Member to leader– Shrinking middle class suggest less

resilience in a community– Connects with Population ecological

research [Gunderson & Holling 2001]

Illustration: http://www.thestar.com/article/540066

Factors Affecting the Growth of Wikipedia

People-ware– Growing resistance to changing content– Coordination cost and bureaucracy

Knowledge-ware: Availability of easy topics to write about Tool-ware: Quality of tools used by editors and admins

http://www.aerostich.com/http://www.mikestreetmedia.co.uk/blog/wp-content/uploads/2009/01/knowledge.jpghttp://youropenbook.agitprop.co.uk/growing.php?p=2

Thank you

Bongwon Suh [email protected]

Augmented Social Cognition Area

Palo Alto Research Center

Monthly Ratio of Reverted Edits

Ecological Growth Model

r, growth rate K, carrying capacity

€

dN

dt= rN(1−

N

K)

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 20100

500000

1000000

1500000

2000000

2500000

3000000

3500000

4000000

Year

r dominateswhen N is small

K dominates when N K ⇒

€

(1−N

K) ≈1

€

(1−N

K) ≈ 0

r/K Selection Theory

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

Evolution cycle– Resilience of an ecological system– Gunderson & Holling 2001

User-Block and Vandalism

Page-Protection and Vandalism

Moore’s Law – Ray Kurzweil’s Extension

http://en.wikipedia.org/wiki/Accelerating_change

Exponential Growth of Computing

http://en.wikipedia.org/wiki/Accelerating_change

The Singularity

“The Singularity is Near” by Ray Kurzweil (2005)

Year 2045– $1000 buys a computer a billion times more

powerful than the human brain.– A.I. surpass human beings as the smartest

and most capable life forms on the Earth.– An extremely disruptive, world-altering event

that forever changes the course of human history.

– There will be a movie!

Logistic Growth Model

Exponential growth model– Growth rate depends on the current N

Ecological population growth model– r, growth rate of the population– K, carrying capacity (due to resource limitation)

€

dN

dt= rN(1−

N

K)

€

dN

dt= r *N

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