Sole, R. V., & Cancho, R. F. I. (2001). The small world of human language. Proc. Royal Society London, 268, 2261-2265.

“…a statistically significant property has been reported about the organization of human language. In spite of the huge number of words that can be stored by a human, any word in the lexicon can be reached with fewer than three intermediate words, on average.

…the graph connecting words in language shows the same statistical features as other complex networks. The short distance between words arising from the SW[Small World] structure indicates that language evolution might have involved the selection of a particular arrangement of connections between words.

If the SW features derive from optimal navigation needs… words the main purpose of which is to speed-up navigation must exist… According to our calculations, the 10 most connected words are `and’, `the’, `of ’, `in’, `a’, `to’, `’s’, `with’, `by’ and `is’. These words are characterized by a very low or zero semantic content.”

Mark Newman : Images of the social and economic world

Child Mortality Rate:

ARPANET (the internet) December 1969

“…a macroscopic snapshot of the Internet for two weeks: 1-17 January 2008. ”

“in 2002.[there were]…926,201 IP addresses and 2,000,796 IP links…[In 2008] The graph reflects 4,853,991 observed IPv4 addresses and 5,682,419 IP links (immediately adjacent addresses in a traceroute-like path) of topology data gathered from 13 monitors probing 48,535,339 /24s spread across 235,286 (49.3% were reached) globally routable network prefixes”