An Introduction to Search Engines and Web Navigation

Chapter 6. DIFFERENT TYPES OF SEARCH ENGINES

"We look at our users' interests, without our users we don't have business."

—Jerry Yang, Cofounder of Yahoo

THERE ARE different types of search engines serving different purposes. We look at web directories, search engine advertising, metasearch engines, personalization of search, question answering engines, image search, and special purpose search engines. All of these variations play an important part in the search engine landscape with the aim of satisfying the diverse needs of users and the commercial objectives of the competing search engines.

CHAPTER OBJECTIVES

• Introduce the notion of a web directory as providing a service, which is complementary to that provided by a standard search engine.

• Explain how a web directory categorizes pages and the problems encountered in keeping the directory up to date.

• Explain how search engine advertising works and how it generates revenues for search engines.

• Show how webmasters can help search engines index their pages with paid inclusions and Sitemaps.

• Discuss banner ads as a form of search engine advertising.

• Explain the notion of sponsored search and how organic and sponsored search engine results must be clearly identified.

• Introduce behavioral targeting, where information is collected about users in order to increase the effectiveness of the advertising.

• Discuss user behavior in terms of the clickthough rate of an ad, the bounce rate of an ad, ad fatigue, users' preference for organic links over sponsored ...