Travel Reference
In-Depth Information
as well as user behaviors of searching (Brin and Page 1998; Jansen and Molina 2006; Jansen and
Spink 2005a). The existing literature related to SEM can be organized according to the 'actors' that
defi ne the components of search engine marketing:
1 the search engine, defi ned as the online tools which algorithmically index, organize and
retrieve relevant web documents and, according to user queries, present those documents in
a pre-defi ned format (Gendler, Ellis, Chang and Davis 2005; Sen 2005);
2 the travel information searcher, defi ned as those travellers who are planning trips or gathering
travel-related information on the Internet (Pan and Fesenmaier 2006); and
3 the online tourism domain, defi ned as the collection of links, domain names and web pages
that contain texts, images and audio/video fi les related to travel and tourism (Pan and
Fesenmaier 2006; Xiang, Wöber and Fesenmaier 2008).
The following three sections review this research with the goal of identifying the underlying
structure and dynamics of search engine marketing.
The search engine
Metaphorically, search engines can be thought of as the 'Hubble Telescope of the Internet' in that
they enable travellers to gain access to billions of web pages that comprise the online tourism
domain (Xiang, Gretzel and Fesenmaier 2009; Xiang, Wöber and Fesenmaier 2008). The major
part of the search engine interface is used to display those results based on the internal ranking
(i.e. organic listing). In addition, major search engines such as Google, display paid advertisements
on the top and right side of major result page, ranked by businesses' bidding price on clicks and
the quality of pages, which is termed a 'Paid Listing.' Paid listings can also appear blended with
organic listings for certain search engines, as they do in Baidu.com (the most popular search
engine in mainland China) and Bing.com. However, the two companies separated the two types
of results under pressure from the public in recent years (Back 2009; Schwartz 2009).
In 2012, Google had 66 per cent of online search volumes, followed by Bing and Yahoo!
(comScore 2012). Among the components of search engines, the algorithm a search engine uses
to rank web pages in organic listings is most important in determining which web pages to
display and in what order. The rank of a web page for certain queries on most popular search
engines determines their online visibility to a large extent (Pan, Hembrooke, Joachims, Lorigo,
Gay and Granka 2007). Given a query, almost all search engines use certain characteristics of web
pages and link structure to rank the web pages (Levine 2000). The characteristics of web pages
include:
1 whether or not the keywords are in the Uniform Resource Locator (URL) of that page;
2 the frequency and size of the keywords on a web page;
3 the keywords in the link anchor text, i.e. pieces of text which contain a link. Usually web
authors imbed meaningful link anchors to provide the user indications of the content on the
linked page. Search engines view link anchors as good summaries of linked pages;
4 alternative text for images, i.e. the text associated with images; and
5 meta-tags, keywords in Titles and Descriptions embedded on a given web page (Cai, Feng
and Breiter 2004).
Some search engines further incorporate the link structure of the web to determine the
importance of web pages (Brin and Page 1998). A web page with many inbound links will be
