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?

vs.

num

ber o

f use

rs in

cat

egor

y(>

40

repl

ies t

otal

)

correlation between focus & % best

music

diseases and conditions

languages homework help

math

biology physics

chemistry

Yes, for technical/factual categories

Does focusing more narrowly correlate with higher quality contribution?

11

mor

e fo

cus -

>hig

her q

ualit

y?

patents

papers

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

. # o

f com

petit

ors i

n ta

sk

log(

inte

rval

) bet

wee

n w

ins

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