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?

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

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

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 # blogs PageRank

What do we have? Blogosphere PageRank Distribution 2006 # blogs PageRank

What has happened? Increase and Decrease (%) of PageRank from 2005 to 2006 percent PageRank

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?

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

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

Use more blogs

Measure PageRank more frequently

Use other indicators/measures (alexa, technorati, BlogLines)

Discuss different metrics