Gooogle is still the only company whose name is synonymous with the verb search
Photo: Mauricio Alejo

The story of Google's algorithm begins with PageRank, the system invented in 1997 by cofounder Larry Page while he was a grad student at Stanford. Page's now legendary insight was to rate pages based on the number and importance of links that pointed to them - to use the collective intelligence of the Web itself to determine which sites were most relevant. It was a simple and powerful concept, and - as Google quickly became the most successful search engine on the Web - Page and cofounder Sergey Brin credited PageRank as their company's fundamental innovation.

But that wasn't the whole story. "People hold on to PageRank because it's recognizable," Manber says. "But there were many other things that improved the relevancy." These involve the exploitation of certain signals, contextual clues that help the search engine rank the millions of possible results to any query, ensuring that the most useful ones float to the top.

Web search is a multipart process. First, Google crawls the Web to collect the contents of every accessible site. This data is broken down into an index (organized by word, just like the index of a textbook), a way of finding any page based on its content. Every time a user types a query, the index is combed for relevant pages, returning a list that commonly numbers in the hundreds of thousands, or millions. The trickiest part, though, is the ranking process - determining which of those pages belong at the top of the list.

Read the rest of the article to understand the awesomeness of Google.