Visible vs. Invisible Web Resources
The Visible Web
The Web pages retrieved as a result of search engine queries or use of a Web directory are called the visible Web. They are readily accessible to anyone conducting an Internet search.
Specialized Online Databases (The Invisible Web)
There are also a variety of full-text or statistical databases available through Internet access. Most of these are not free. Some examples include your library's online catalog, electronic versions of print journals, or government documents. Your college library may provide online access to more common databases such as EbscoHost, ProQuest Newspapers, GaleNet Databases, CQ Researcher, Ethnic Newswatch, RAND California, and many, many others. Some of these databases include full-text magazine or newspaper articles. Others may contain reference, statistical or biographical data.
Usually off-campus access to these proprietary databases is limited to those who have been issued a user name and a password. Students at Hartnell College have access to online databases on campus without a logon and off campus by using their Cat Card barcode number (you must first register with the library for this service).
The invisible Web is also composed of online multimedia that may not be detected or indexed by search engine or search directory spiders. To access these Internet resources, the researcher must rely on additional tools such as specialized directories or portals. For a more information, please read this online article that discusses The Invisible Web.
The search techniques you used to look for information using search engines, search directories and meta search engines are the same one you can use to conduct research in online catalogs and invisible web databases.
The main difference between Invisible Web resources such as reference databases and those found by search engine queries is the quality of the information each contains. As a general rule, reference databases offer scholarly, peer-reviewed materials.
Compare the quality of information from a database such as Access Science with what you discover when conducting the same search using Ask.com. Which provides the best source for information?
The following tutorials will provide additional background on Invisible Web resources: