Internet search engine result diversity, relevance, quality and the effects of search engine opitmization

During the last decade, Internet search engines have become a popular and increasingly effective technology both in daily information seeking and in the business world. Nowadays, however, there exists very limited research work in this area. Existing studies have primarily relied upon methods and theories originated from prior research in traditional Information Retrieval Systems.

This dissertation is the first in-depth study of Internet search engines with an expanded view of an Information Retrieval System and its applications. On the one hand, it proposes a new framework of relevance assessment. On the other hand, it addresses the online advertising aspect of Internet search engines. Neither expansion has been adequately addressed in existing research in the domain of Internet search engines.

The dissertation is composed of three independent studies compiled into chapter 2 through chapter 4, respectively. As the content on Internet continues to grow and new indexing technologies become available, Internet search engines are facing an increasing challenge of ranking search results. The impact of the diversity of search results on the performance of search engines has not been systematically examined. The first study aims to address this research issue by proposing a new framework of relevance assessment base on Information Attributes. With an analytical model, the impacts of both diversity and information seeking method have been identified.

The second study empirically tests the findings of the first study. In addition, the study uses search engine quality as the dependent variable. With controlled experiments and a factorial design, the study confirms some of the findings of the first study. Inconsistent findings and implication have been discussed.

The third study aims to answer the research question of "What is the impact of Search Engine Optimization (SEO) on the online advertising market". This study builds an economic model that reveals the impact of SEO on the market price of paid placement and the sustainability condition of SEO firms.

Together, the three studies explore and build theories in several untapped areas of Information Retrieval and the online advertising market. The practical and theoretical implications have been discussed in the concluding chapter.