Identifying Domain Experts in the Blogosphere -- Ranking Blogs Based on Topic Consistency

Current ranking algorithms, such as Page Rank, Technorati authority, and BI-Impact, favor blogs that report on a diversity of topics since those attract a large audience and thus more visitors, links, and comments. On the other side, niche blogs with a very specific topic only attract a small audience and thus have only a small reach. This results in a low ranking from today´s blog retrieval systems. We argue that the consistency of a blog, i.e. how focused an author reports on a single topic, is a sign for expert knowledge. To find these blogs is particular important for other domain experts to identify blogs that they would like to follow and stay in active contact. To ease the retrieval of expert blogs, i.e. to separate them from the mass of blogs that report on random topics, we introduce a metric for blogs based on topic consistency. We divide the consistency ranking in four different aspects: (1) intra-post, (2) inter-post, (3) intra-blog, and (4) inter-blog consistency. By evaluating the metric with a test data set of 12,000 crawled blogs, we demonstrate the plausibility of our approach.