1. 9 Algorithms: PageRank

2. Ranking
After matching, have to rank:

3. Ranking with Links
Links are a sign of importance:

4. Identifying Authority
Links into a page give it authority
Page value = sum of authorities of pages linking to it

5. Issues
Cycles: …

6. Random Surfing
Instead of counting links, randomly surf them

7. Link Quality Not all links are equal Who do you trust? CS Prof
World Famous Chef

8. Random Surfer In Use
We assume that more important pages will have more incoming links

9. The Real Math Markov Chains Set of states
Each state has probability of leading to other states
Represent as matrix

10. Excel Simulation
Three pages:

11. Link Quality
More links is easy to abuse
Spam Link Pages

12. Issues Spam Links Discourage with negative weight Spam Link Pages -1

13. Limitations Still have issues/room for growth Link Spam
Context of link
Where link is on page
"Bob's recipe is terrible" vs "Bob's recipe is great"
Lack of semantic knowledge
Page's Authority should not be the same for all domains

14. "If you're not paying for the product, you are the product."
Power
Controlling search is power:
"If you're not paying for the product, you are the product."