Investigating usage of the vivisimo clustering search engine interface

Various interface and algorithmic techniques are under developments to assist Web searchers with managing the volume of information available on the Web. Clustering of the Web search engine results is one such area. User searching with clustered results in operational Web environments is not well understood. This paper reports on Web usage analysis of Vivisimo.com, which is a Web meta-search engine that dynamically clusters users' search results in real time. The research questions are: 1) What are the characteristics of Web searching on a clustering search engine, such as Vivisimo?, 2) How are searchers interacting with clustered results?, and (3) What are the visitation patterns of searchers using Vivisimo? We analyzed data collected from 25 April - 2 May 2004, representing 100% of site traffic. Results show that approximately 50% of searchers who interact with results do use clusters, but only 2% of interactions go beyond the top-level clusters. These results provide new insight into search characteristics with a cluster-based Web search engine and point to the need for better results visualization methods.