1. Offense: Planetary-Scale Views on a Large Instant Messaging Network J. Leskovec, et al.

2. As a whole…  Provides a strong analysis  Considers a variety of approaches  However, it falls prey to a number of critical pitfalls  Provides a strong analysis  Considers a variety of approaches  However, it falls prey to a number of critical pitfalls

3. The Data Set  Only includes data from MSN Messenger  Other networks may have different usage patterns  Paper suggests MSN accounts for ~50% at the time (seems to be correct)  Each network could draw an entirely different type of user (CompuServe vs. AOL)  What about spam/bots?  Are these a relevant portion?  Only includes data from MSN Messenger  Other networks may have different usage patterns  Paper suggests MSN accounts for ~50% at the time (seems to be correct)  Each network could draw an entirely different type of user (CompuServe vs. AOL)  What about spam/bots?  Are these a relevant portion?

5. Communication Demographics  Only look at ages 10-60, to correct for any misrepresented ages  Any theoretical backing?  Conversations depend only on number of messages  What about non-symmetric conversations? (one user sending messages, another not replying)  Only look at ages 10-60, to correct for any misrepresented ages  Any theoretical backing?  Conversations depend only on number of messages  What about non-symmetric conversations? (one user sending messages, another not replying)

6. World Geography and Communication  Show us distribution of MSN users by World population  What does this really tell us?  Better to instead look per capita to computer users?  Perhaps internet use?  Would take into account areas where no one is on the internet and therefore not on MSN  Show us distribution of MSN users by World population  What does this really tell us?  Better to instead look per capita to computer users?  Perhaps internet use?  Would take into account areas where no one is on the internet and therefore not on MSN

7. The Communication Network  Only consider those who communicated during time period  A limitation of the data set  Doesn’t acknowledge the possibility of large amounts of potential links that were just not active during the month  Really need a larger data set to deal with this  Only consider those who communicated during time period  A limitation of the data set  Doesn’t acknowledge the possibility of large amounts of potential links that were just not active during the month  Really need a larger data set to deal with this

8. Milgram  Data is not actually comparable to Milgram’s!  Milgram focused on drawing connections with a letter  These connections are more incidental (based around some sort of social network, but are not “focused” in the same way)  Many people may be “on a first name basis” with someone, but just not normally talk to them  Data is not actually comparable to Milgram’s!  Milgram focused on drawing connections with a letter  These connections are more incidental (based around some sort of social network, but are not “focused” in the same way)  Many people may be “on a first name basis” with someone, but just not normally talk to them

9. Milgram  Temporally incomparability  This data relies only on 1 month of communication  In Milgram’s study, people could use anyone that they knew on a first name basis  A whole lifetime!  Implication: MSN may be much better connected than these results show!  Temporally incomparability  This data relies only on 1 month of communication  In Milgram’s study, people could use anyone that they knew on a first name basis  A whole lifetime!  Implication: MSN may be much better connected than these results show!

10. A Purpose?  All this information is good to know  But what can we really do with it?  Generally speaking, seems people use it as an extension of their real world networks  Experiment like this unable to describe any motivation, which would be helpful  All this information is good to know  But what can we really do with it?  Generally speaking, seems people use it as an extension of their real world networks  Experiment like this unable to describe any motivation, which would be helpful