Algorithms For Dummies

  Getting the Right Web page 

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IN THIS CHAPTER

 

» Understanding why finding what you 

want on the web is hard

 

» Reviewing problems that PageRank 

solves

 

» Implementing the PageRank 

algorithm with teleporting

 

» Learning how PageRank usage is 

evolving

Getting the Right 

Web page

T

he last few chapters review graphs at length. The web is one of the most 

interesting examples because of its extent and complexity. After providing 

an understanding of the basic algorithms that allow graph traversal and 

extraction of useful structures (such as the presence of clusters or communities), 

this chapter concludes the discussion of graphs by presenting the PageRank algo-

rithm that has revolutionized people’s lives as much as the web and Internet did 

because it makes the web usable. PageRank isn’t only the engine behind Google 

and many other search engines, but it’s also a smart way to derive latent informa-

tion, such as relevance, importance, and reputation, from a graph structure.

Libraries rely on catalogues and librarians to offer an easy way to find particular 

texts or explore certain subjects. Books aren’t all the same: Some are good at pre-

senting certain kinds of information; some are better. Scholar recommendations 

make a book an authoritative source because these recommendations often appear 

in other books as quotes and citations. This sort of cross-reference didn’t exist on 

the web initially. The presence of certain words in the title or in the text of the 

body recommended a particular web page. This approach is practically like judg-

ing a book by its title and the number of words it contains.

Chapter 

11

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  PART 3