A First Study on Temporal Dynamics of Topics on the Web.

While much work has been devoted to understanding Web dynamics and using this knowledge to efficiently maintain the freshness of the indexes of generic search engines, the same is not true for domain-specific indexes constructed by focused crawlers. For the latter, the problem is compounded by the fact that it is important not only to maintain already-crawled pages fresh, but also to identify new relevant content and expand the collection. In this paper, we discuss the challenges involved in this problem and describe our preliminary efforts in building a testbed to better understand the dynamics of specific topics and characterize how they evolve over time. We propose a data collection methodology and a set of experiments to answer important questions about temporal dynamics and evolution of topics. We also present the results of the experimental analysis we carried out using data collected over a period of four weeks using two distinct topics. These results suggest that topic-specific refreshing strategies can be beneficial for focused crawlers.