This story appeared last week in the New York Times and is one of the best I’ve seen in a while on Google. Posted here for future reference.
“Google does more than simply build an outsized, digital table of contents for the Web. Instead, it actually makes a copy of the entire Internet — every word on every page — that it stores in each of its huge customized data centers so it can comb through the information faster.
As Google compiles its index, it calculates a number it calls PageRank for each page it finds. This was the key invention of Google’s founders, Mr. Page and Sergey Brin. PageRank tallies how many times other sites link to a given page. Sites that are more popular, especially with sites that have high PageRanks themselves, are considered likely to be of higher quality.”