Several posts discussed the economic and social systems that underpin virtual worlds and creative works. catrionag describes some of the markets and auction systems used to allocate items in World of Warcraft and similar MMORPGs. There are interesting parallels here with many of the issues that have come up in class. Interesting questions have also been raised in the press about what happens when the “virtual economy” of such games comes into contact with the economy of the off-line world.

ltdtl writes about mapping the social networks in Shakespeare’s plays, and particularly about tools to study the changes in the network over the course of the story. A number of earlier studies have considered whether the structure of social networks in fiction precisely match social networks in real life, or whether there are recurring differences; this is not a fully resolved issue. (One of the more detailed studies was done in 2002 on the Marvel Comics Universe (truly), joining two characters if they appear in the same comic book.)

A number of recent posts on the class blog have discussed the importance of social networks in the fabric of communities. timo writes about differences in the patterns of strong and weak ties in small villages versus urban or suburban settings in highly developed parts of the world. icarus discusses a recent study indicating that people have access to increasing numbers of social connections, but that the number of strong ties per person is shrinking. The news article linked from the post quotes Robert Putnam, whose book Bowling Alone is one of the more extensive recent works to document this phenomenon. zachlipton writes about a study on the social network structures that surround entrepreneurs, and notes that the social network links one uses for emotional support may be different than those used for problem-solving or task-directed goals. It’s definitely true that in the discussion on weak ties, one of course shouldn’t forget that strong ties are crucial too, as is the interaction between strong and weak ties. See also the recent paper by Shi, Adamic, and Strauss on networks of strong ties.

The role of networks in politics, law, and civic infrastructure is a theme in several posts. np2007 discusses some of the privacy issues in creating on-line medical databases, and by extension, in creating digital records of other personal data such as social networks. By way of further background, Latanya Sweeney at Carnegie Mellon has done extensive research on the privacy dangers inherent in medical databases and other on-line records; the possibility of privacy breaches in anonymized social network data is the subject of a paper that Lars Backstrom, Cynthia Dwork, and I have just written.

yl328 discusses the social network Barack Obama has started as part of his campaign. There has been discussion on-line about the extent to which candidates have been purchasing keyword-based ads on their own names; keyword-based advertising is an upcoming topic in the course that combines networks, search, and auctions in novel ways. jtblogger writes about research to create social-networking sites that can allow people to maintain contact with one another and with current information in the event of a large-scale disaster. mrlite discusses a study of the interactions and competition between different stock exchanges, pointing out that this is closely aligned with the motivation behind our lecture on models of markets with nodes representing traders.

Finally, in the context of network models in other areas of science and applied mathematics, jle38 discusses network models of the brain — an area of increasing interest — and notes that networks of neurons showed up as one of the original model systems in Steve Strogatz and Duncan Watts’s highly influential 1998 paper on small-world networks. rebelkingismyhero posts about papers on probabilistic models of networks: to build a concrete mathematical model of a large complex network, one approach is to suppose that it is generated at random (according to some specified distribution). We’ll be looking at probabilistic models like this later in the course.