This material has been developed to accompany:
"Searching and Researching on the Internet and the World Wide Web, Fourth Edition" ISBN 1-59028-036-9
"The Information Searcher's Guide to Searching and Researching on the Internet & the World Wide Web" ISBN 1-887902-58-9

Directories and Virtual Libraries 

Topics

Characteristics of Directories Two Major Directories and How to use Them
Browsing and Searching Directories Virtual Libraries
 
Activities
Yahoo!  HotBot
The Argus Clearing House The Librarians' Index to the Internet

One of the ways to find information on the World Wide Web is to use directories.

Directories, or subject catalogs, are especially useful for those with such general questions as

Directories can also help you find the best resources on a particular topic.

Virtual libraries are the most specialized of all directories. They are therefore the best places to find sites that collect Internet resources on a particular topic.

Check our annotated lists of selected directories and virtual libraries for some of the more popular ones.

Characteristics of Directories

Directories are topical lists of Internet resources arranged in a hierarchical way. Although they are meant to be browsed by subject, directories can also be searched by keyword. They differ from search engines in one major way-the human element involved in collecting and maintaining the information. Directories are created and maintained by people, whereas search engines rely on spiders or robots to scour the Internet for links. There are a number of differences between directories. One way to determine directories' particular characteristics is to ask the following questions about each of them: Each directory differs from others mainly in the level of quality control involved in its management. For example, some directory managers have very little control over their collections, relying on Web page submitters to provide annotations and decisions about where their resource should be placed in the directory's hierarchy. Other directory managers are much more selective not only about which resources they include, but also about where in the subject hierarchy the pages will be located.

Some directory editors write detailed annotations of the pages. These annotations can be evaluative, descriptive, or both. Annotations are Web page descriptions that either the Web page submitter or the directory editor attaches to the Web pages. Many annotated directories also rate Web resources using criteria that vary from one directory to another.

There are also directories that are made up of the most popular Web pages found by programs that count how many pages have hyperlinks to these sites. Web pages that are popular may be very different from ones that are rated as excellent.

Of all the directories, virtual libraries rely most on human beings in selecting and controlling the resources included in their collections. Virtual libraries are organized in a way that tames the Internet's chaotic nature and thus attempts to create a more traditional "library-like" setting in which to do research.

The human element involved in creating and maintaining directories creates both advantages and disadvantages for the user. Some of the inherent strengths of directories can be weaknesses, and vice versa.

Strengths

The major advantages of using directories are as follows: Because directories rely on people to select, maintain, and update their resource lists, they contain fewer resources than search engine databases. This can be a plus, especially when you are looking for information on a general topic. It's a lot easier and less time-consuming to go through a list of 50 or so Web pages than to sort through the thousands of pages that a search engine may present. In addition, many directories rate, annotate, analyze, evaluate, and categorize the resources included, which helps you find resources of the highest quality.

We discuss the evaluation of Internet resources in detail  in our Web page "Evaluating Information on the World Wide Web", but now is a good time to bring up the issue of quality control and filtering of WWW sites. With thousands of resources appearing on the Web each day, it is important that there are people working to determine which sites and Web pages on the World Wide Web have the highest quality. For example, if we want to find some of the best Web pages on alternative medicine, we could try the Open Directory Project. You can browse through the list of resources until you find one or more that may be useful to you.

Weaknesses

There are three major disadvantages inherent in World Wide Web directories. They are as follows: One of the major disadvantages of using some directories is that the hierarchical arrangements may be arbitrary. For example, let's say we are looking for information on ozone depletion. We want to start by finding a few sites. We decide to use Yahoo!, one of the best-known directories on the Web.

Note that Ozone Depletion is located under the subcategory or subheading Environment and Nature, which is located under the top-level category Society and Culture. The people who organized this directory chose this hierarchy. Another directory might place Ozone Depletion under the top-level category Science. The ability to search Yahoo! and most other directories by keyword solves this problem of arbitrary hierarchical arrangements.

Another drawback is that selecting, rating, and categorizing Web pages take a lot of time, so directories tend to be less up-to-date than search engine databases, which are constantly updated by computer programs that automatically gather new Web pages.

The third disadvantage inherent in directories is also an advantage-the resources are chosen by people who subjectively decide which ones are best. What seems a good resource to one person may not to the next. This is why it is important for the directory management to have well-stated criteria for selecting and rating resources.

Browsing and Searching Directories

There are two ways to find information in directories. You can browse by subject or search by keyword. These will be discussed in the following section.

Browsing

Browsing a directory is not difficult. You simply click on a subject category that you think will contain the subject you are seeking. This will take you to another level in the hierarchy, where you will choose another subject from the list of subjects that appear on your computer screen. You then examine the choices that are returned to you and select the one most closely related to your research topic. You continue this process until your screen fills with a list of resources that you can then examine to find the information you need.

Sometimes this process has two levels; other times it has several. It depends on the directory and how detailed the subject is. For example, if we were to browse the Lycos directory for resources about economics, we would start by clicking on the top-level category Science & Technology. Next, we would click on Social Science, and from the resulting list of subcategories, we would choose Economics.

Now, let's try to find economics resources in Yahoo! The top-level category we need to click on is Social Science.

If you don't find any resources on the topic you are looking for while browsing, you can use the Back arrow on your browser to return to another level. There, you can try a different subject heading that may lead you to successful results.

Searching

By now, you can probably see the advantage of being able to search a directory. It may be difficult to determine where in a directory's hierarchy a particular subject will be found. Searching a directory is not the same as searching the Web using a search engine. The primary difference is that when you search a directory, you have access to only those resources that are included in the directory, not the entire Web. Also, in some directories (such as Yahoo!), you do not search the full text of Web pages; you search only the words in the URLs (Uniform Resource Locators), the titles of the Web pages, and annotations (if they exist).

Note the advantage of searching versus browsing. A search (often) produces sites on the subject that are under different categories in the directory.

Two Major Directories and How to Use Them

In this section, we will discuss two well-known directories, pointing out their differences, similarities, and special features by doing some hands-on activities with them. The three directories we'll be using are Yahoo! and HotBot.

Activity Yahoo!

Overview

Yahoo!, http://www.yahoo.com, is the most comprehensive directory on the World Wide Web. Yahoo! relies on Web page submitters to annotate and categorize the resources that are included, so some sites have a brief descriptive note, and some do not. Some sites in Yahoo! will link to a review, but most will not. Yahoo! strives to be extensive; consequently, there is minimal filtering of resources. You can browse Yahoo! or search it by keyword. When you perform a search in Yahoo!, the first results are from the directory, listed by relevance to the search topics. At the same time, a search engine, will automatically perform your search for you. By clicking on Web sites at the top of the results screen, you'll see the results from the search engine listed. In the following activity, we'll browse for information in Yahoo!, and then we'll search for the same information using the search query interface that Yahoo! provides. We'll be looking for some general information on the Human Genome Project. We don't know much about it and want to find a general information page.

We'll follow these steps:

  1. Go to the home page for Yahoo!
  2. Browse Yahoo! for information on the Human Genome Project.
  3. Bookmark the Web page or add it to your list of favorites.
  4. Search Yahoo! for information on the Human Genome Project.
  5. Access the Web pages that the search engine retrieved.

(See the book for the details.)

Activity HotBot Directory

Overview

The HotBot Directory Overview In this activity, we'll use HotBot to find resources about distance learning in colleges and universities. HotBot, unlike Yahoo!, is fundamentally a search engine, but it has a directory as well. You can browse HotBot's Directory and you can search the search engine. Let's see how the HotBot Directory works.

We'll follow these steps:

  1. Go to the home page for the HotBot Directory.
  2. Browse the HotBot Directory for distance learning resources.
  3. Search HotBot for Web pages on distance learning.

(See the book for the details.)

Virtual Libraries: Directories with a Difference

Virtual libraries are directories with resources that librarians or cybrarians have organized in a logical way. Virtual libraries are often referred to as annotated directories as well. It is helpful to think of these specialized directories as being similar to libraries, because people who are committed to finding the very best resources on the Internet have carefully selected and maintained the resources in a virtual library. These people usually rate or analyze the resources and arrange them so they will be found easily. See our annotated list of virtual libraries for a collection of some of the more popular ones.

There are three major types of resources that virtual libraries are most apt to contain: subject guides, reference works, and specialized databases. Subject guides are Web resources that include hyperlinks to sites on that particular subject. Reference works are full-text documents, such as dictionaries, encyclopedias, almanacs, and so forth. Specialized databases are searchable indexes that catalog certain types of material, such as journal article citations, financial data, and so forth.

Activity   The Argus Clearinghouse

Overview

Let's say you are interested in doing research on the Middle East. Unsure of which particular issue or country you are interested in researching, you would like to see a subject guide to the World Wide Web on the subject of the Middle East. A virtual library would be an excellent place to begin this search. Since The Argus Clearinghouse is a virtual library, let's start there.

The Argus Clearinghouse is a virtual library provided by Argus Associates. The resources included in The Argus Clearinghouse cover most subject areas. Subject specialists from all over the world write the subject guides, and subject specialists on the Argus staff rate and analyze each guide. You can browse and perform keyword searches in The Argus Clearinghouse. In this activity, we will illustrate how to browse the directory.

Let's explore The Argus Clearinghouse by following these steps

  1. Go to The Argus Clearinghouse.
  2. Browse for subject guides on the Middle East.
  3. Search for a Middle East subject guide.

If you find a subject guide on the topic you are researching, it can save you a lot of time and energy by helping you navigate the Web's vast sea of information.

(See the book for the details.)

With the Argus Clearinghouse's search capability, we picked up one relevant subject guide that the structured browse didn't produce. This is another example of how keyword searching can enhance results. We could easily see the difference between a virtual library and a Web directory such as Yahoo! A virtual library such as the Argus Clearinghouse is very selective about the Web resources that are included and the way they are rated. Keep in mind that virtual libraries are very small collections of Web resources, so they may not always have what you need.

Activity The Librarians' Index to the Internet

Overview

The Librarians' Index to the Internet (LII) is a virtual library that contains over 3,500 annotated and evaluated resources in most subject areas. The LII can be searched as well as browsed. The LII operates with a grant from the California State Library. It was initiated and is still maintained by Carol Leita, a librarian. The annotations are written by Ms. Leita and other librarians from the state of California. The index is part of the Digital Library Sun SITE at the University of California, Berkeley. The Librarians' Index to the Internet is organized a lot like Yahoo!, so you should feel familiar with it quickly.

We're going to use the LII to find the "Blue Book" for automobiles. A virtual library is the best place to go to find a reference source like this. If you searched a search engine like AltaVista or HotBot for blue book, you could easily retrieve thousands of hits. The other advantage to using a virtual library for this type of information is that you may find other automobile resources for consumers that may be helpful. First, we'll browse the appropriate categories to locate it and then we'll search the directory by typing blue book in the search form.

We'll follow these steps:

  1. Go to the Librarians' Index to the Internet.
  2. Browse the library's directory for the Blue Book for automobiles.
  3. Search the library's directory for the Blue Book.

(See the book for the details.)

Virtual libraries are the places to go if you are looking for a reference source like a dictionary, handbook, encyclopedia, or special database. The Librarians' Index to the Internet is a good resource to have on your bookmark or favorites list.

Topics
Characteristics of Directories Two Major Directories and How to use Them
Browsing and Searching Directories Virtual Libraries
 
Activities
Yahoo!  HotBot
The Argus Clearing House The Librarians' Index to the Internet
Visit Searching and Researching on the Internet and the WWW for more information about using the Internet for doing research and finding what you need.
This material has been developed to accompany: by Ernest Ackermann and Karen Hartman, and published by Franklin, Beedle and Associates, Incorporated, Wilsonville OR.

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Ernest Ackermann Department of Computer Science, Mary Washington College, University of Mary Washington