PageRank

The PageRank algorithm is what made Google the premier search engine. PageRank creates a measure of the importance of a web page allowing search results to be ordered with the highest quality results first. PageRank uses the link structure of pages. It can be seen as as the steady state of a Markov process or drunkards walk randomly fllowing links, equivalently a matrix algebra solution finding the maximum eigenvector for the link matrix, or as a form of spreading activation. Note that the modern Google search uses many additional heuristics and modifications to the original PageRank.