Implicit Structure and Dynamics of Blogspace

1
Implicit Structure and Dynamics of Blogspace

• Lada Adamic
• Accelerating Change 2004
• (joint work with Eytan Adar, Li Zhang, and Rajan
  Lukose)

2
Blogs and the digital experience

• Use
• Record real-world and virtual experiences
• Easy to record and discuss things seen on the
  net
• Structure blog-to-blog linking
• Use Structure
• Great to track memes
• ideas spreading in the blogosphere like an
  epidemic

3
Our interest

• Macroscopic patterns of blog epidemics
• How does the popularity of a topic evolve over
  time?
• Microscopic patterns of blog epidemics
• Implicit Explicit
• Who is getting information from whom?
• Ranking algorithms that take advantage of
  infection patterns

4
Tracking Blogs

• Blogdex Earliest example
• Lets you see which blogs (and when) linked to a
  site
• Others emerged with similar/related functionality
• Can find epidemic profiles (popularity over time)
• Our question do different types of information
  have different epidemic profiles

5
For Example
Popularity
Time
6
Clusters reflect different epidemic profiles
Major News front page More delayed death
(broader interest)
Slashdot huge surge followed by sharp
drop (slashdot-effect)
7
Clusters
Products, etc. Sustained over a period of time
Major-news site (editorial content) back of the
paper
8
Microscale Example Giant Microbes
9
Microscale Dynamics

• What do we need track specific epidemics?
• Timings
• Graphs

b1
t0
Time of infection
t1
10
Microscale Dynamics

• Challenges
• Root may be unknown
• Multiple possible paths
• Uncrawled space, alternate media (email, voice)
• No links

bn
b1
?
?
t0
Time of infection
t1
11
Microscale Dynamics who is getting info from whom

• Explicit blog to blog links (easy)
• Via links are even better
• Implicit/Inferred transfer (harder)
• Use ML algorithm for link inference problem
• Support Vector Machine (SVM)
• Logistic Regression
• What we can use
• Full text
• Blogs in common
• Links in common
• History of infection

12
Visualization

• Zoomgraph tool
• Using GraphViz (by ATT) layouts
• Simple algorithm
• If single, explicit link exists, draw it
• Otherwise use ML algorithm
• Pick the most likely explicit link
• Pick the most likely possible link
• Tool lets you zoom around space, control
  threshold, link types, etc.

13
Giant Microbes epidemic visualization
via link
inferred link
blog
explicit link
14
iRank

• Practical uses of inferred epidemic information
• Can use a simpler inference (timing)
• Finding good sources
• Invisible authorities

b1
True source
b2
Popular site
b3
b4

b5
bn
15
iRank Algorithm

• Draw a weighted edge for all pairs of blogs that
  cite the same URL
• higher weight for mentions closer together
• run PageRank
• control for spam

t0
Time of infection
t1
16
Do Bloggers Kill Kittens?

• Friday morning Wired writes
• "Warning Blogs Can Be Infectious.

17
Research at the Information Dynamics Lab at
HP http//www.hpl.hp.com/research/idl ladamic_at_h
pl.hp.com