A brief description based on edi parisier work "the filter bubble" . Lets starts with a description of common ranking algorithms, for google and jobrap and then focus on the great edi parisier work.

2. @MARCELLOSOUND
http://www.linkedin.com/in/marcelloborzi

5. "IF IT ISN'T ON GOOLE IT DOESN'T EXIST"
JIMMY WALES, WIKIPEDIA FOUNDER

6. PAGERANK
“THE MORE LINKS YOU GET, THE MORE IMPORTANT YOU ARE”
http://www.google.com/competition/howgooglesearchworks.html

7. http://en.wikipedia.org/wiki/PageRank#Simplified_algorithm

8. http://en.wikipedia.org/wiki/PageRank#Simplified_algorithm

9. http://www.google.com/competition/howgooglesearchworks.html

10. GOOGLE +1 : 0.40
FACEBOOK SHARES : 0.34
NUMBER OF BACKLINKS : 0.34
FACEBOOK TOTAL : 0.34
FACEBOOK COMMENTS: 0.34
PINTEREST: 0.31
TWEETS : 0.28
BACKLINKS REF=NOFOLLOW: 0.25
http://www.searchmetrics.com/en/services/ranking-factors-2013/

11. MARK ZUCKENBERG , FACEBOOK CEO

12. http://www.whatisedgerank.com/

13. WHAT IS AFFINITY?
Affinity is a one-way relationship between a User and an
Edge. It could be understood as how close of a
"relationship" a Brand and a Fan may have. Affinity is built
by repeat interactions with a Brand's Edges.Actions such
as Commenting, Liking, Sharing, Clicking, and even
Messaging can influence a User's Affinity.
http://www.whatisedgerank.com/

14. WHAT IS WEIGHT?
Weight is a value system created by Facebook to
increase/decrease the value of certain actions within
Facebook. Commenting is more involved and therefore
deemed more valuable than a Like. In the weighting
system, Comments would have a higher value than a Like.
In this system all Edges are assigned a value chosen by
Facebook. As a general rule, it's best to assume Edges
that take the most time to accomplish tend to weigh more.
http://www.whatisedgerank.com/

15. WHAT IS TIME DECAY?
Time Decay refers to how long the Edge has been alive;
the older it is the less valuable it is. Time Decay is the
easiest of the variables to understand. Mathematically it is
understood as 1/(Time Since Action).
As an Edge ages, it loses value. This helps keep the
News Feed fresh with interesting new content, as
opposed to lingering old content.
http://www.whatisedgerank.com/

16. http://www.whatisedgerank.com/

26. UPWORTHY
LEFT-WING POLITICAL
MOVEON.ORG
INTERNET ACTIVIST
AVAAZ.ORG
http://en.wikipedia.org/wiki/Eli_Pariser

27. http://www.brainpickings.org/index.php/2011/05/12/the-filter-bubble/

28. http://www.brainpickings.org/index.php/2011/05/12/the-filter-bubble/

29. http://www.brainpickings.org/index.php/2011/05/12/the-filter-bubble/

30. http://www.brainpickings.org/index.php/2011/05/12/the-filter-bubble/

33. THE ECONOMIST
http://www.brainpickings.org/index.php/2011/05/12/the-filter-bubble/