This past week we saw a number of interesting applications of network theory on graphs ranging from social to business to information networks. Two especially insightful posts discussed voter networks in the United States and the importance of social networks in the music industry. In his article on voter networks, pastafarian1859 examined the different phenomenon of “blue states” and “red states” in the US over the last several election cycles. Another compelling perspective on this issue would be that of Schelling’s segregation model in which nodes voluntarily segregate themselves in order not to be a minority. Could it be that Democrats and Republicans voluntarily segregate themselves into certain parts of the country? How might this play into the urban and rural dynamics that the author discussed?

In a very interesting article on the potential Yahoo-Microsoft merger, elashish14 explored the situation from the perspective of an unstable three-node network. Since Yahoo, Microsoft, and Google all compete in the online search market, it models easily to one of the simple examples in which a triad can be unstable: three negative edges joining each node. Since we know that this situation cannot last due to its structural imbalance, one could have used the underlying economics to predict Microsoft’s bid. In a purely logical world, when this sort of structure arises, it must come to pass that two of the nodes will ultimately team up so that we have two clusters of all positive edges connected to each other by all negative edges, a situation very close to what we see unraveling.

Another intriguing post, this time about an information network, looked at how YouTube became blocked in much of the world due to the single action of a Pakistani ISP. The author, mdc53, considered the incident a failure of the network and raised a number of compelling questions about network vulnerability and security.  “If a country as relatively small and undeveloped as Pakistan could very easily accidentally disrupt YouTube’s traffic and block the site for users worldwide, then what sorts of cyber-chaos and confusion could potentially be unleashed by a malevolent country or group? Furthermore, what’s to prevent something like this from happening again, and do certain internet protocols need to be revised or reworked?”  These are important questions that are probably being examined in the light of the recent incident.