There are some interesting new insights and explication of previous work in a modern context and responds to Harvard's John Palfrey criticism at the same time.. The one that is powerful is his explanation of Power law as it applies to interactivity online and notably, blogs. There have been interesting papers, notably with contributions from Elizabeth Lane Lawley, Clay Shirky, Ross Mayfield, Sébastien Paquet & Jessica Hammer.
In response to some ideas of David Sifrey Jason Kottke did the math.
Back in 2003 he noted:
The dotted blue line is a linear equation, the dashed red line is a quadratic equation, and the solid black line is the power law equation. The linear and quadratic equations fit the data poorly. So the quadratic is an improvement over the linear equation, but neither compare to the excellent fit of the power law.
What this means for PR people is interesting and comes from another part of the book dealing with the nature of networks online.
First the power law part. Bloggers range from people with a lot of followers, who because they have so many, cannot be very interactive with them all, to the blogs at the nexus of a few chums (who interact a lot with a few). This means that the 'average' blogger is probably a long way down the curve and 'average' is a meaningless approach to identifying influence.
We come across the power law a lot in online activities. Wired magazine's editor-in-chief Chris Anderson in article in October 2004 where he coined the expression 'The Long Tail' shows a commercial interpretation.
But the next part is also important. His explanation that to achieve connectedness (and enter the illusive 'viral' nature of the internet), then it is the properties (like blogs) that have very modest numbers of connections that are the most powerful.
In public relations terms and to identify content that will move people to respond to a brand or issue, it is not the people or online properties with the profile of publishing (Boing Boing being the apogee example) , it is the people with much more modest numbers of links that really count.
In a part you can see this in the scatter.com video that Anthony Mayfield has on his blog:
The notable elements are that this is a continually morphing process, that the most powerful influence is not from the big broadcasters but from the many smaller nodes interacting and range of elements that contribute to both connectedness and significance.
Online PR is not about big numbers it is about a range of changing and relatively small nodes that have a small interaction with other nodes. It is the number of small blogs that is important not sheer reach.