1. Defense: Knowledge Sharing and Yahoo Answers: Everyone Knows Something L. A. Adamic, et al.

2. Why study Knowledge Sharing?  It is a rising method of communication (YA, Wikipedia)  It differs from the classic model of a few authoritative sources  Current implementations differ from the traditional forum format  Opportunity to study interaction between people (always useful!)  It is a rising method of communication (YA, Wikipedia)  It differs from the classic model of a few authoritative sources  Current implementations differ from the traditional forum format  Opportunity to study interaction between people (always useful!)

3. …but is it social networking?  Yes!  There are regular users  Often have reused identities  Can become familiar with each other  Form networks of those who ask and those who answer  Most importantly:  It is real people communicating, sharing ideas, etc.  Yes!  There are regular users  Often have reused identities  Can become familiar with each other  Form networks of those who ask and those who answer  Most importantly:  It is real people communicating, sharing ideas, etc.

4. Why Yahoo! Answers?  The largest English language question- answer site  Broad audience  Avoids bias of more specific purpose sites  Covers many topics  Provides a non-standard social networking methodology  Does not allow traditional forum style  The largest English language question- answer site  Broad audience  Avoids bias of more specific purpose sites  Covers many topics  Provides a non-standard social networking methodology  Does not allow traditional forum style

5. Cluster Analysis  Classify question categories by  Thread length  Asker/replier overlap  Content length  Classify question categories by  Thread length  Asker/replier overlap  Content length

6. Cluster Analysis  Provides a clear breakdown of categories of questions  Directly acknowledges the issue of the content of the questions  A good starting point, raises further questions about the nature of YA  Who is asking?  Are they the same people asking in each category?  Provides a clear breakdown of categories of questions  Directly acknowledges the issue of the content of the questions  A good starting point, raises further questions about the nature of YA  Who is asking?  Are they the same people asking in each category?

7. Degree Distributions  Form graph by connecting users who ask to users who answer

8. Ego Networks  Shows connectedness of neighbors  In general, discussion topics are more connected  Larger strongly connected components  Factual answer topics are less connected  People who ask, aren’t answering  In fact, are less connected than a random graph of this size  Shows connectedness of neighbors  In general, discussion topics are more connected  Larger strongly connected components  Factual answer topics are less connected  People who ask, aren’t answering  In fact, are less connected than a random graph of this size

10. Motif Analysis  Provides a further sense of “who responds to who”  Further indicates differences between categories  Provides a further sense of “who responds to who”  Further indicates differences between categories

11. Network Structure Analysis  Provides insight into the structure of the network  How information flows in different categories under the same umbrella format  Could tailor the design of similar sites to the nature of the topics  Optimize sharing information of certain types  Provides insight into the structure of the network  How information flows in different categories under the same umbrella format  Could tailor the design of similar sites to the nature of the topics  Optimize sharing information of certain types

12. Network Structure Analysis  Provides strong indicators of the nature of user interaction  How is a given user going to use this service?  Ex: Discussion based have most mutual edges, perhaps better suited towards different model  Provides strong indicators of the nature of user interaction  How is a given user going to use this service?  Ex: Discussion based have most mutual edges, perhaps better suited towards different model

13. Expertise  Analyzed 100 random selections from programming section  Rated 1-5 (1 basic, 5 “pro”)  Found that only 1% was above a level 3  Analyzed 100 random selections from programming section  Rated 1-5 (1 basic, 5 “pro”)  Found that only 1% was above a level 3

14. Expertise  Admittedly not a definitive sample!  Still an important hint about nature of YA  The questions seem shallow because they likely are  The fact that much of the information may be trivial is unimportant  Still an important topic to look into  Admittedly not a definitive sample!  Still an important hint about nature of YA  The questions seem shallow because they likely are  The fact that much of the information may be trivial is unimportant  Still an important topic to look into

15. User Entropy  Analyzed the distribution of answers from users across categories  Generally well spread out  Some users are very focused, very low entropy  But a high number have very high entropy, ask and answer many questions  Analyzed the distribution of answers from users across categories  Generally well spread out  Some users are very focused, very low entropy  But a high number have very high entropy, ask and answer many questions

16. Entropy Analysis  Emphasizes the breadth of YA  Many people are interested in many topics  Suggests the strengths of having a general site instead of something more tightly focused  As pointed out, this may be at the sacrifice of depth  Again, helps to build a user profile  Who is using this service? And for what?  Emphasizes the breadth of YA  Many people are interested in many topics  Suggests the strengths of having a general site instead of something more tightly focused  As pointed out, this may be at the sacrifice of depth  Again, helps to build a user profile  Who is using this service? And for what?

17. Best Answers  YA allows the asker to pick a best answer, or other users to vote  Found:  People seem to like longer answers  No correlation between entropy across all categories and overall percentage of best answers (but some for top-level categories looking for expertise)  Reply length, track record good indicators  YA allows the asker to pick a best answer, or other users to vote  Found:  People seem to like longer answers  No correlation between entropy across all categories and overall percentage of best answers (but some for top-level categories looking for expertise)  Reply length, track record good indicators

18. Best Answers  Provides a sense of what other users take to be most insightful  An important issue in Knowledge Sharing  In categories where applicable, raises question of correlation with the actual best answer  Another element not found in traditional forum  Provides a sense of what other users take to be most insightful  An important issue in Knowledge Sharing  In categories where applicable, raises question of correlation with the actual best answer  Another element not found in traditional forum

19. Best Answers  Provides an analysis of the Best Answer in terms of the category type  Compare to E. Agichtein, et al. Finding High- Quality Content in Social Media, WDSM’08, 2008 which focuses on the answer quality  Provides an analysis of the Best Answer in terms of the category type  Compare to E. Agichtein, et al. Finding High- Quality Content in Social Media, WDSM’08, 2008 which focuses on the answer quality

20. So why was all this good?  Provides a first look at diverse, large scale question-answer network  Not attempting to delve into the intricacies of Yahoo! Answers  Acknowledges a number of issues that arise in such a model (Breadth vs. Depth)  High school homework problems  Provides a more well defined picture of structures and user interactions  Provides a first look at diverse, large scale question-answer network  Not attempting to delve into the intricacies of Yahoo! Answers  Acknowledges a number of issues that arise in such a model (Breadth vs. Depth)  High school homework problems  Provides a more well defined picture of structures and user interactions