Introduction to searching

The internet is a vast network which is constantly expanding and which contains several different types of information source, such as web pages, newsgroups and file archives. Although it is easy to stumble across data on almost any topic one might imagine, because of the internet's vastness, it can often be extremely difficult to obtain answers to specific questions or to obtain very particular information.

Probably the most common way used to search for information on the internet is to "surf the net" or, in other words, simply to browse across various web wages by following whatever links take your fancy. Net surfing can be a fun activity and often leads to wonderful discoveries but, by its very nature, it readily tempts the searcher away from the point of their search. In addition, unless a very considered approach is taken when choosing which links to follow, the results may be of little value and cause a great deal of frustration.

Fortunately, it is not too difficult to increase your likelihood of search success. By adopting a structured approach to browsing and by combining that strategy with the use of an appropriate "search engines" you can soon become proficient at locating that elusive piece of information.

Types of search engine

Search engines are the librarians of the internet. Search engines parallel the librarian's expertise in the conventional library search in two main ways: firstly, because they can help to strucure the search for maximum relevancy, and secondly because they can direct the search towards the types of source information most likely to include the required data.

There are several types of search engine on the internet, each with its own characteristics and strengths:

• * Subject Trees or Directories

  * Keyword indexes

  * Multiple & Meta Indexes

  * People finders

Subject Trees

Subject trees are probably the best first step beyond unstructured browsing and can provide a useful starting point for a search which can then be refined further by keyword searching in its later stages.

Subject trees (also known as subject guides or directories) provide a search method similar to browsing the shelves in a bookshop or library, where books of the same topic are grouped together. The subject tree provides a hierarchy of topics and their subdivisions which assist the searcher to reach specific information because unrelated resource categories are eliminated.

An important characteristic of subject trees is that it is people (as opposed to computers) who select which sites are to be included and people who allocate those sites to the various subject cateogories. Whilst this process can allow for review of sites and the weeding of poor quality or offensive sites, it is also time-consuming and subjective and may lead to less current or more restricted listings.

The overall usefulness of a subject tree will depend to a great extent on the clarity of its design and the extent to which its coverage and subdivision of a topic matches the understanding of the searcher. Because there is not necessarily any consistency between two subject trees which index the same topic, and because the expertise of the designers varies widely, it should be noted that the use of subject trees can, at times, be problematic and frustrating.

Subject trees do, nonetheless, provide an excellent introduction to more structured searching for newcomers to the internet and, particularly when used in conjunction with keyword searching, will increase search success.

Selected Subject Trees

Name & URL	Type of Content	Organisation	Features
Argus Clearinghouse http://www.clearinghouse.net	Business, Education, Medicine	Broad categories	Ratings system
The Aussie Index http://www.aussie.com.au/index/ai.htm
AustLII http://www.AustLII.edu.au/links/Australia/Subjects	Legal information C'th , NSW & ACT Acts & Regulations. Court decisions	Source & subject indexes	Listing of other legal indexes.
A2Z (Lycos) http://a2z.lycos.com
BUBL http://www.bubl.ac.uk	Areas of interest to the academic community Library information	UDC classified access Alphabetical access	Regularly updated Site annotations Listings maintained by subject specialists
Excite http://www.excite.com/
Galaxy http://www.einet.net/galaxy.html	Sites submitted by creators on a range of general topics	Broad categories	Cross references Links to other subject directories
Magellan http://www.mckinley.com
This is Australia http://springboard.telstra.com.au/index.html
WebCrawler http://www.webcrawler.com/
WWW Virtual library http://vlib.stanford.edu/Overview.html
Yahoo http://www.yahoo.com

Keyword indexes

Keyword search engine facilitate searching on a particular word, phrase or concept. The site listings of keyword search engines are gathered not by people but by computers. The 'robots' or 'spiders' which index the sites work constantly in the background to add new sites to the listings. Whilst this method produces many more listings than do the subject guides, it can also produce many less relevant and undesirable sites.

Keyword search engines can be characterised (loosely) by the way in which they deal with the following :

• * The choice and sophistication of search options

  * Which types of documents are indexed

  * What elements of documents are indexed

  * The number of documents indexed

  * The way in which results are reported

The types of search offered by the various engines range from those that offer only relatively simple search options to those that offer complex capabilities such as the use of boolean operators (and, or, not), proximity searching (near), and concept searching.