Using PageRank to determine the distribution of attention
Lars Kirchhoff | Axel Bruns | Thomas Nicolai
Investigating the impact of the blogosphere
18.10.2007
What are the questions?► Is the impact of the blogosphere
different to other forms of online media?
► How is PageRank distributed across the blogosphere?
► Does it indicate the existence of measurable, visible effects of blogs on the overall mediasphere?
► Has there been a growth in the impact of the blogosphere on the Web over the two years analysed here?
What we have done?2005► ~15m profiles from blogger.com► ~8.871m unique blog urls extracted► Retrieved Google PageRank
2006► same profiles ► but slightly more unique blog urls
extracted (~8.888m)
► Retrieved Google PageRank
Why PageRank?► Available for almost any web page
► Easy to gather
► Global property that takes the whole web into account
► Search is most common way to look for information
What do we have?Blogosphere PageRank Distribution 2005
# b
log
s
PageRank
1
10
100
1000
10000
100000
1000000
10000000
0 1 2 3 4 5 6 7 8 9 10
Distribution 2005
What do we have?
1
10
100
1000
10000
100000
1000000
10000000
0 1 2 3 4 5 6 7 8 9 10
Distribution 2005
Distribution 2006
Blogosphere PageRank Distribution 2006#
blo
gs
PageRank
What has happened?Increase and Decrease (%) of PageRank from 2005 to 2006
perc
en
t
PageRank
0
20
40
60
80
100
120
0 1 2 3 4 5 6 7 8 9 10
What does this mean?► Strong decline at PageRank 1,2 / 7-10
► Lower end: effect of focus on Blogger?► Blogger as sandbox high attrition?
► Higher end: shrinking A-list?► churn away from Blogger?► harder to achieve high PageRank in larger, more
diverse Web?
► Need to track trajectories► e.g. how many low PR blogs rose from 2005 to
2006?► e.g. how many PR7+ blogs survived from 2005 to
2006?
What are the limitations?► Coarse values
► Algorithm is not entirely known
► Updates for Google PageRank are random
What next!► Use more blogs
► Measure PageRank more frequently
► Use other indicators/measures(alexa, technorati, BlogLines)
► Discuss different metrics
