Finding information on the World Wide Web has been compared to being in the world's largest library and not having access to a card catalog or information desk. Selecting the appropriate search tools can overcome these limitations.
There are three major classifications of Internet Search Tools:
Directories are man-made databases that organize sites by subject areas - not unlike a subject-based library card catalog. Sites are reviewed by the directory's staff and classified under some appropriate topic heading. For example, a school district web page, might be found under Education/K-12/school/sites/.
The most famous directory is the Yahoo database. Yahoo contains 14 subject areas and each area also contains several subtopics. Yahoo also offers many other services besides its directory. It has free E-mail, auctions, news, weather, sports, chat rooms, online shopping, etc. A site like Yahoo that contains numerous features and activities is known as a Portal.
Yahoo is based on a hierarchy of subjects. For example, to find web sites that contain Social Studies lesson plans, the user would navigate through a series of topics and subtopics:
Yahoo also contains a children's site - Yahooligans, which offers a watered down subject list and filtering of inappropriate materials.
The Argus Clearinghouse is a site that lists topical guides to select Internet-based information. The guides are evaluated on a scale of five checkmarks. This site has high standards and is very selective about its listings.
The advantages of using Yahoo and other directories are that they are easy to navigate and present a good starting point if you just want to browse what's available under a subject area. A directory provides a wide scope of info listed under broad topic headings. Searching is also possible; however, you will only be searching the directory's database. In Yahoo, if an item isn't found in the Yahoo database, the site defaults to an Internet search engine.
Directories such as Yahoo only cover a small
percentage of the sites available on the web - less than 3%. Most
directories are not very good for finding very specific information. If
you're looking for very specific information try using a search engine.
Search engines are software programs that traverse
web servers and index the files they collect. This software is known as a
spider, robot or crawler. The spider visits a web page, reads it, and then
follows links to other pages at that site. The spider returns to the site
periodically to update any changes.
The indexes that are created can be collected from
the title, full-text, URL, etc. An index is sometimes known as a
catalog. It may take a while for new pages or changes that the spider
finds to be added to the index. The user utilizes an interface that allows
entry of keywords into a search box. When you do a keyword search, the
search engine matches your query words against all the records it has in its
indexed databases to present a listing of possible documents meeting your
request. Boolean or logical operators (AND,
OR, NOT) can be used on many search engines.
The results of the keyword search or query are
displayed in relevancy ranked order. Every search engine has a different
algorithm (formula) for ranking the display of relevant hits. The
algorithm usually looks at the keywords location and frequency on the page and
will generally rank pages high with keywords found in the title and repeated
Not all search engines are created equal. Database size varies and performance is linked to how often updates are made, the number of unique hits, and the number of inactive or dead links.
Search engines contain a much larger and more current database than a directory search tool. They also allow the use of Boolean operators or special syntax.
Can present an overwhelming number of results that
may not be relevant to the original search request. Users must read the
help files contained in the search engine documentation. Unfortunately,
not all search engines share the same syntax.
AltaVista is a portal site that presents numerous search options. Its simple search interface supports pseudo-Boolean syntax and the advanced search tool can handle Boolean queries. There are four tabs above the Search box that toggle users between an advanced search, Images, MP3/Audio, and video search screens.
AltaVista also claims to index more of the Internet than any other search engine and also has the capability to conduct searches in different languages. Raging Search is a recent AltaVista product that is a search-only site.
Fast Search is a simple, uncluttered, easy-to-use, quick search engine. It does not display advertisements and portal buttons to distract your attention. It has both a simple and advanced search interface. The simple search supports pseudo-Boolean syntax and the advanced search filters words through drop-down menus. Domain filtering, filtering for offensive content and support for multiple languages are also available at this site. Search interfaces for MP3, multimedia and a listening room are provided through Lycos.
Google is a clean interface search engine unencumbered by clusters of buttons, adds and links. Its PageRank function indicates the number of Web pages that point to a particular document and determines which pages to display first. It also includes an "I'm Feeling Lucky" button that displays the search engines top pick. Another interesting feature is Google's cache function. Each page found after a search is automatically saved so if a link you need no longer exists, clicking on the "Show matches (Cache)" link will display the last saved version of the page.
HotBot is powered by the Inktomi search engine. Featured on this search site is an easy to set collection of fine-tuning controls that work without using Boolean operators. These controls appear in drop-down menus in both the standard and advanced search interfaces. Also featured are word filters, specific date ranges and domain choices. The site also includes subject categories, links to commercial sites, E-mail, etc. Boolean syntax, wild cards and case-sensitive searching are also supported. The site utilizes the Direct Hit popularity engine, which includes a list of the ten most visited sites for your query.
The Northern Light search engine groups search results into "custom folders" based on subject, document type, source and language, that enables more efficient location of relevant information. There is also support for Boolean syntax, nested queries, wildcards and truncation. In the Power Search mode, searches can be limited by date, language, and type of Web page (.edu, .org, etc.). Another unique feature of this site is a fee-based special collection of articles not available elsewhere.
Boolean or logical operators (AND, OR, NOT) are not universally accepted by all search engines. It's important to read the help files of the search engine you intend to use.
Steps in constructing a keyword search:
a) Identify keywords
b) Use Boolean or logical operators, if allowed. (AltaVista, Excite, Fast Search, HotBot, Lycos)
c) Use Pseudo-Boolean or implied operators. (+ -) (AltaVista Simple Search, Excite, Fast Search, Google, HotBot, InfoSeek, Lycos)
d) Phrase Searching
e) Capitals and Plurals
f) Title Search (AltaVista, Fast Search, HotBot, InfoSeek, Lycos, Northern Light)
A meta-search engine utilizes a number of search engines at the same time. It uses a keyword search method similar to a search engine. The results are either listed by the search engine used or integrated into a single listing.
AskJeeves is a meta-search engine that supports natural language searching. Users can enter a question in plain English and then choose a relevant website by selecting it from a pull-down menu and and clicking on the ASK! button.
Dogpile searches up to 25 other search engines. It also permits the user to specify which search engines to use by choosing "Custom Search" under "Dogpile destinations."
MetaCrawler developed by the University of Washington in 1994 does not maintain an internal database. Keyword queries are sent to several Web search engines, including AltaVista, Excite, InfoSeek, Lycos, etc. The results are collated into a single list with duplicate entries deleted. MetaCrawler also allows sorting by relevance and source.
Can produce results when other search tools do not. They are also tolerant of inaccurate or imprecise search syntax.
Are not as effective for difficult searches as a search engine as they may present a large number of irrelevant results.
a) when searching a broad topic or
idea to research.
Use a search engine:
a) when a simple search using a
directory is unsuccessful.
The search engine ditto.com specializes in finding pictures on the Web. A user can either enter keywords in a search field or browse through 16 subject categories. The site also supports an advanced search interface that allows queries by picture type, file size, color depth, picture width and height, and date added. The site claims to filter offensive or inappropriate images from its image database. Boolean and pseudo-Boolean operators are supported. In addition, filename, URL, and title searches are supported.
AltaVista also allows for image searching. The feature is contained in a separate tab on the main page. Filter criteria allow the user to choose among photos, graphics, buttons/banners, color or black and white. Support is also included for domain, host, media, title, and URL contexts.
The Amazing Picture Machine contains a list of sites on graphical resources on the Internet.
Please keep in mind that it is necessary to obtain permission from the image owner or source on copyrighted images before using the graphic on a web page.
Britannica Internet Guide is an interesting portal site that allows users to search, the Britannica Encyclopedia, reviewed web sites, magazine articles and related books. The site provides good coverage of general interest topics.
INFOMINE contains a collection of scholarly Internet resources relevant to higher education.
MapQuest is a website totally devoted to maps. The interface allows the user to input an address and an interactive map is returned. Driving directions can also be obtained. The site also contains a Yellow and White Pages directory and a travel and city guide section.
Most search engines do not filter out sites that may contain pornography, violence, and hate-filled messages. Search tools for children mainly use humans to review indexed sites, unlike adult search engines which rely on software called spiders or web-bots to search out files on web servers. Consequently, the size of children's search engine databases are much smaller than the search tools using web-bots.
Listed below are search engines and directories designed for children. The details on what is filtered out varies from site-to-site. It's recommended that you read the help or about files to determine the extent of filtering.