Summary

In this chapter, we learned about the PageRank algorithm developed in the late 1990s by the future founders of Google and their colleagues at Stanford. It revolutionized the world of search engines by providing an effective way to sort search results in such a way that much more relevant web pages to users' searches could be displayed at the top of the list.

We began by reviewing how search engines worked before PageRank, some prior innovations, and the general shortcomings of web search before PageRank.

Then, we moved on to applying a single PageRank update for a small "internet" of just five web pages introduced in Chapter 5, Elements of Discrete Probability. Instead of computing the formulas one by one by hand, we wrote a matrix form of the calculation and showed that it replicated the results from the previous chapter. We also learned that PageRank usually runs over and over until the PageRank vector converges to a steady state, which we did by running...