Identifying influential bloggers: WSDM 2008

Citation

Nitin Agarwal, Huan Liu, Lei Tang, Philip S. Yu, "Identifying the Influential Bloggers in a Community", Proceedings of the International Conference on Web Search and Web Data Mining (WSDM), 2008.

Online version

Available at Citesteer

Summary

This paper aims at identifying most influential bloggers in a blogging community. The paper first proposes some metric for assessing how influential a blog post is. Then the authors perform some experiments on blogs from few blog sites and qualitatively evaluate their results.

What makes a Blog influential

Recognition: An influential blog post is recognized by many, which can be judged by the number of in-links ($\iota$), i.e. the number of other posts referencing the particular post.
Activity Generation: A blog post that generates more activity is supposedly more influential. This is measured by the number of comments made on the blog post ($\gamma$).
Novelty: Novel ideas are supposed to be more influential [1]. A post that references more other posts (or has more out-links) is supposed to have lesser novel ideas. So novelty can be taken as negatively correlated with the number of out-links ($\theta$).
Eloquence: More eloquent posts are more influential [1]. Authors use the length of the blog post ($\lambda$) as a measure of eloquence.

Measuring Influence

The authors define a concept called InfluenceFlow. They conjecture that blog-influence flow can be thought of as a graph. For a post p having no. if in-links $\iota$ and no. of out-links $\theta$, the InfluenceFlow is defined as:
$InfluenceFlow(p)=w_{in}\Sigma (m=1\ to\ \iota )I(p_{m})-w_{out}\Sigma (n=1\ to\ \theta )I(p_{n})$
Where w_{in} and w_{out} are the weights that can be adjusted for incoming and outgoing influences; p_m denotes the blog post that links to the post p, and p_n denotes the post to which the post p links; I(p_x) is the influence score of the post p_x. Note that unfortunately the paper doesn’t mention how I score is computed from the four parameters discussed above. Authors further define the influence I for a post in terms of the InfluenceFlow, which looks weird, since they’ve already used I score in defining InfluenceFlow.
$I(p)\propto w_{com}\gamma _{p}+InfluenceFlow(p)$
Where $\gamma _{p}$ is the no. of comments made to the post p, and w_{com} is a regulating coefficient. For the constant of proportionality, authors use a measure of the quality of the blog. However, the measure used by authors is quite naive and is actually a function of the length of the blog post $w(\lambda )$. So
$I(p)=w(\lambda )*(w_{com}\gamma _{p}+InfluenceFlow(p))$
Authors further define $iIndex(B)$ for a blogger B as $max(I(p_{i}))$ where $I(p_{i})$ is the influence score of a post made by blogger B. The higher the value of $iIndex$ for any blogger, more influential they are considered.

Results

Two metrics were used: R-Precision and NDCG. NDCG is described in [2].

References

[1] D. Shen, Q. Yang, J.-T. Sun, and Z. Chen. Thread detection in dynamic text message streams. In Proc. of SIGIR ’06, pages 35–42, Seattle, Washington, 2006.
[2] K. Jrvelin and J. Keklinen. IR evaluation methods for retrieving highly relevant documents. In Proc. of SIGIR ’00, pages 41–48, Athens, Greece, 2000.