Barabasi, A.L., Linked (2003) The Third Link: Six Degrees of Separation, pp. 25-35

Summary
Barabasi claims that the unbelievably small number of links can connect two randomly selected nodes in a network. According to him, so-called “six degrees of separation” is a good example. It originates from an experiment performed by a Harvard professor, Staley Milgram. The result of experiment told us that two randomly selected person are separated by only 5.5 persons on average in United States. Barabasi and other people also conducted an experiment, and estimated that the number of links necessary to connect two documents in Web is 18.59 on average. Barabasi insists the average degrees of separation in a network can be calculated with mathematical method.

Reaction
Although Barabasi’s opinion is interesting, he seemed to ignore the influence on human interrelationship by technology. Contrary to the age Milgram live in, now we have a number of Web technologies which connect us very easily and quickly. For example, SNS is close to “social search engine” (p.32), which Barabasi regards impossible. Of course SNS is an example and is still undeveloped, but Barabasi should take into consideration the influence of such technologies.