Gateways and subject-specific databases

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By: www.sc.edu

There are two kinds of gateways: library gateways and portals. (See Lesson 3 for a discussion of portals.) Library gateways are collections of databases and informational sites, arranged by subject, that have been assembled, reviewed and recommended...

Added: 30 April 2008 Views: 137

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Gateways
There are two kinds of gateways: library gateways and portals. Library gateways are collections of databases and informational sites, arranged by subject, that have been assembled, reviewed and recommended by specialists, usually librarians. These gateway collections support research and reference needs by identifying and pointing to recommended, academically-oriented pages on the Web. See list of examples below.

Subject-Specific Databases (sometimes called "Vortals")
Subject-specific databases, or vortals (i.e., "vertical portals") are databases devoted to a single subject, created by professors, researchers, experts, governmental agencies, business interests, and other subject specialists and/or individuals who have a deep interest in, and professional knowledge of, a particular field and have accumulated information and data about it. See list of examples below.

There is a large portion of the Web that search engine spiders cannot, or may not, index. It has been dubbed the "Invisible Web" or the "Deep Web" and includes, among other things, pass-protected sites, documents behind firewalls, archived material, the contents of certain databases, and information that isn't static but assembled dynamically in response to specific queries.

Web profilers agree that the "Invisible Web," which is made up of thousands of such documents and databases, accounts for 60 to 80 percent of existing Web material. This is information you probably assumed you could access by using standard search engines, but that's not always the case. According to the Invisible Web Catalog, these resources may or may not be visible to search engine spiders, although today's search engines are getting better and better at finding and indexing the contents of "Invisible Web" pages.

In order to access so-called "Invisible Web" sites, you need to point your browser directly at them. That's what many library gateways and subject-specific databases do. They are good sources for direct links to database information stored on the "Invisible Web."

Use library gateways when you are looking for high quality information sites on the Web. You can be fairly certain that these sites have been reviewed and evaluated by subject specialists for their accuracy and content.

Use subject-specific databases when looking for information on a specific topic, e.g., news links, multimedia files, archives, mailing lists, people, job finders, and thousands of databases devoted to specific topics of interest. Today, more and more of the so-called "main-stream" search engines, subject directories and portals are pointing to these subject-specific databases, using direct links on their home pages.