1. Oozing out knowledge in human brains to the Internet Lada Adamic School of Information University of Michigan http://www.ladamic.com

2. 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)

3. can we identify experts? fragment of the Java Forum Q&A network Zhang, Ackerman, Adamic, WWW 2007

6. ego-network structure of a technical forum programming Adamic et al., WWW 2008

7. network structure of a discussion forum politics

8. Marc Smith: “This proves that marriage is more like wrestling than like programming” 8 Image: Eytan Bakshy What can the network structure of Q&A forums tell us about interactions? programmingmarriagewrestling

9. Does focusing more narrowly correlate with higher quality contribution? vs.

10. number of users in category (> 40 replies total) correlation between focus & % best music diseases and conditions languageshomework help math biology physics chemistry Yes, for technical/factual categories Does focusing more narrowly correlate with higher quality contribution?

11. more focus ->higher quality? 11 patents papers Wikipedia Q&A Adamic et al., First Monday 2010

12. persistence and quality even the most active users have intermittent activity intermittency negatively correlated with quality Nam, Ackerman, Adamic, CHI 2009

13. 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

14. what to answer? filling in the blanks: users select unanswered questions correcting others: last answer picked as best most often

15. 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

16. Taskcn knowledge sharing community Askers offer cash rewards for best “solution” to task

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

18. users learn to choose less competitive tasks av. # of competitors in task log(interval) between wins

19. 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

20. Q: can collaborative work yield better solutions than individual efforts? – individual ideas & exploration – merging the best – e.g. Netflix prize

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

22. 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.eduladamic@umich.edu http://www-personal.umich.edu/~ladamic