For the ones that don't know, traditionally, to measure an article's importance there the method is to have ?citing number?, meaning all the times that that article has been quoted by somebody else. The idea is that if many different people quote an article, this means that this article is worth while and important. Well, apparently Google isn't looking only to this, but also to the content of the article.

Researchers have found out that the Google algorithm, when measuring a web site's importance , offers a systematic method to find important articles . The google index proved better that the traditional method to find the really good scientific articles, that were't that much quoted by others but which were proven to be of a very high value.

Sidney Redner and Pu Chen from the University of Boston and Huafeng Xie and Sergei Maslov from the National Laboratory of Brookhaven found out that certain articles that proved to be very influential . Like the article of Wigner and Seitz, from 1933 "On the Constitution of Metallic Sodium" , which is now University book regular content. Another example is the article of Gauber from 1963 about "Photon Correlations", which receive the Nobel Prize last year. These articles weren't known using the regular quoting algorithm, but shower up very high in google and were given a very high PR.

The way google does it is by allowing his spiders to dig deep into the quoting web and see how many times the article that quoted the first article was quoted, and so on, meaning that if the article that quoted your article is of great value, also your article increases in value.