Catalysts for Change - Ethics for the Information Age - page 37

FIGURE 1.17 Using the Web, you can access up-to-date traffic information from many major
cities. (Copyright © 2011 by WSDOT. Reprinted with permission.)
Computer on Christmas Day 1990. He called his browser WorldWideWeb. In March
1991 he released the browser to some computer users at CERN.
The first widely used Web browser was Mosaic, developed at the University of Illi-
nois, Urbana-Champaign. Today, the most popular Web browsers are Chrome, Internet
Explorer, Firefox, and Safari. These browsers enable Web surfers to retrieve text, still
images, movies, songs, computer programs—in theory, anything that can be digitized.
The Web has also become a convenient way for organizations to provide access to news
updates and dynamically changing information (Figure 1.17).
1.4.9 Search Engines
A search engine is a program that accepts a list of keywords from a user, searches a data-
base of documents, and returns those documents most closely matching the specified
keywords. Today the term search engine is most frequently used to describe programs
that search databases of Web pages. Web search engines are the most powerful informa-
tion retrieval devices ever invented. The most popular Web search engine, Google, has
indexed billions of Web pages.
There are two types of Web search engines. Crawler-based search engines, such
as Google and AltaVista, automatically create the database of information about Web
pages. In a process similar to Web surfing, programs called spiders follow hyperlinks,
eventually visiting millions of different Web pages. Summary information about these