Oozing out knowledge in human brains to the Internet

Lada AdamicSchool of InformationUniversity of Michigan

http://www.ladamic.com

Oozing out knowledge

Knowledge In ``Knowledge search is like oozing out knowledge in human brains to the Internet. People who know something better than others can present their know-how, skills or knowledge''

NHN CEO Chae Hwi-young

“(It is) the next generation of search… (it) is a kind of collective brain -- a searchable database of everything everyone knows. It's a culture of generosity. The fundamental belief is that everyone knows something.” -- Eckart Walther (Yahoo Research)

can we identify experts?

fragment of the Java Forum Q&A network

Zhang, Ackerman, Adamic, WWW 2007

ego-network structure of a technical forum

programming

Adamic et al., WWW 2008

network structure of a discussion forum

politics

8

Marc Smith: “This proves that marriage is more like wrestling than like programming”

Image: Eytan Bakshy

What can the network structure of Q&A forums tell us about interactions?

programming marriage wrestling

Does focusing more narrowly correlate with higher quality contribution?

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diseases and conditions

languages homework help

math

biology physics

chemistry

Yes, for technical/factual categories

Does focusing more narrowly correlate with higher quality contribution?

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patents

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WikipediaQ&A

Adamic et al., First Monday 2010

persistence and quality

• even the most active users have intermittent activity• intermittency negatively correlated with quality

Nam, Ackerman, Adamic, CHI 2009

Why?

• What motivates users to answer hundreds to thousands of questions?

• From interviews of Naver (Korean Q&A site) participants– Altruism– Learning– Hobby– Business– Points

what to answer?

• filling in the blanks: users select unanswered questions• correcting others: last answer picked as best most often

Many answers you can get for free…What do you need to pay for?

TaskCN: popular Chinese Witkey site

Jiang, Adamic, Ackerman, ICWSM 2008, EC 2009

Taskcn knowledge sharing community

• Askers offer cash rewards for best “solution” to task

How virtual points & real bucks influence participation in Q&A forums

users learn to choose less competitive tasksav

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Field experiment

• Crowdsourcing: 120 translation tasks– all pay auction mechanism: participants

contribute solutions, only 1 is selected to receive payment

– price treatment: high, low– shill treatment: enter in our own solution as a

user with or without prior success

• results– monetary incentives incentivize spam

(85% are machine translations)

– higher pay yields better contributions

– shills discourage other quality contributions

Liu, Yang, Adamic, Chen

Q: can collaborative work yield better solutions than individual efforts?

– individual ideas & exploration– merging the best– e.g. Netflix prize

Q: what is the role of “community” in retaining workers?

for more info• Crowdsourcing and knowledgesharing: strategic user behavior on TaskCn

Yang, J., Adamic, L., Ackerman, M.S., EC2009• Questions in, KnowledgeIn?

Nam, K., Ackerman, M.S., Adamic, L., CHI 2009

• Competing to share expertise Yang, J., Adamic, L., Ackerman, M.S., ICWSM2008

• Examining knowledge sharing on Yahoo Answers Adamic, L., Zhang, J., Ackerman, M.S., Knowledge Sharing and Yahoo Answers: Everyone knows something, WWW’08

• ExpertiseRank algorithms and evaluations Zhang, J., Ackerman, M.S., Adamic, L., Expertise Networks in Online Communities: Structure and

Algorithms, WWW’07

Lada Adamic ladamic@umich.eduhttp://www-personal.umich.edu/~ladamic