Overview of the TREC 2007 Blog Track

The goal of the Blog track is to explore the information seeking behaviour in the blogosphere. It aims to create the required infrastructure to facilitate research into the blogosphere and to study retrieval from blogs and other related applied tasks. The track was introduced in 2006 with a main opinion finding task and an open task, which allowed participants the opportunity to influence the determination of a suitable second task for 2007 on other aspects of blogs besides their opinionated nature. As a result, we have created the first blog test collection, namely the TREC Blog06 collection, for adhoc retrieval and opinion finding. Further background information on the Blog track can be found in the 2006 track overview [2]. TREC 2007 has continued using the Blog06 collection, and saw the addition of a new main task and a new subtask, namely a blog distillation (feed search) task and an opinion polarity subtask respectively, along with a second year of the opinion finding task. NIST developed the topics and relevance judgments for the opinion finding task, and its polarity subtask. For the blog distillation task, the participating groups created the topics and the associated relevance judgments. This second year of the track has seen an increased participation compared to 2006, with 20 groups submitting runs to the opinion finding task, 11 groups submitting runs to the polarity subtask, and 9 groups submitting runs to the blog distillation task. This paper provides an overview of each task, summarises the obtained results and draws conclusions for the future. The remainder of this paper is structured as follows. Section 2 provides a short description of the used Blog06 collection. Section 3 describes the opinion finding task and its polarity subtask, providing an overview of the submitted runs, as well as a summary of the main used techniques by the participants. Section 4 describes the newly created blog distillation (feed search) task, and summarises the results of the runs and the main approaches deployed by the participating groups. We provide concluding remarks in Section 5.