A Search Engine is a tool or a software that helps a web surfer locate specific information on the web.
Normally, a search engine has a search box that looks like this:

In addition to a list of general subjects to restrict your search.
e.g Universities, Law, Medicine, Computer, Internet, Health, Games, etc..

The most famous search engines on the Internet are:
Yahoo, HotBot, Altavista, Lycos, Webcrawler, Infoseek and Excite.

Search engines are grouped into 2 categories:

• Directory search engines.
• Index or Spider search engines.

Directory search engines are used when searching for general information. Usually, the search results are
displayed and grouped into categories.  If you are searching for Universities, Companies or Countries use directory search engines. Yahoo is the most popular directory.

Index or Spider search engines are used when searching for something specific. The search engine searches
the content of a webpage stored in its database, so when querying a search engine like Altavista you're actually searching its database and not the whole Internet. The search engine might return website addresses or just individual pages of a website matching your query.

If you're looking for "food" you'd better use a Directory like Yahoo, you will get irrelevant results when using index search engines because the index search engine matches the words you have entered in the search
box with the content of a website, many irrelevant websites might contain the word "food" and appear in the search results page.

The following are searching techniques applicable to almost all search engines:

- Phrase Searching:  Use it when searching for a specific subject. For instance, if you're looking for
Internet Solutions you should type "Internet solutions", put the 2 words between quotations, so you will
only get webpages containing both words (next of each other). Suppose you've typed internet solutions without the quotes, what you will get is pages that contain the word internet and other pages with the
word solutions, most probably the result page will contain thousands of irrelevant pages.

- title searching: Searching by title is not supported by all search engines, however it is very useful with
Altavista and allows you to get accurate results. By typing title: followed by the search word or phrase,
the search engine will only look for pages that contain the word or phrase in the page title (this is the title
you get at the top of a webpage e.g teckies.com online magazine). The logic behind this technique is that
websites that talk about the dangers of smoking should at least contain the word smoking at the title.

- Boolean Operators: Maybe you wonder what math got to do with search engines, well boolean operators
come very handy when searching on the Internet. By combining operators such as AND, OR, NOT you can control the results you get thus search more efficiently. Let us take a look at those magical operators.

• AND: Use the Boolean AND in capital letters between your keywords and you will only get webpages
  that contains both words. If you want to search for apple pie just type apple AND pie.
  
• OR: OR operator is used between keywords to get pages that contains either of the keywords.
  For instance typing bike OR car will get webpages that contain the keyword bike and others that
  contain the word car.
  
• NOT: NOT operator is used to eliminate pages that contain a keyword. For instance typing
  Clinton NOT Monica will dump all pages that mention the Monica Lewinski scandal.

In addition to Boolean operators you can use (+) to add keywords just like AND and minus (-) to discard certain keywords from search results. Make sure you don't use any space between the sign and the keyword
e.g +space -nasa will get webpages that contain the word space and dump those with the word nasa.

P.S: All Boolean operators should be capitalized, otherwise they will be treated as a keyword.


Which technique gives better results ?

There's so magical formula to get what you want from a search engine, it depends on what you're looking
for, you are often advised to try several techniques to see which one yields better results on a particular
search engine even combine techniques. For instance your can use phrase searching with boolean logic
e.g "space travel" NOT "fiction" this will return pages that only contain "space travel" phrase and dump all
pages with the word "fiction".
As mentioned earlier, title searching is very efficient especially with Altavista, for instance if you want to
look for some Windows tutorials on Altavista, simple type title: windows tutorials and see what you get.

The best thing to do when searching on the Internet is that you should stick with one search engine, don't spend time jumping from one engine to another, instead take a look at the search engine's help page to see which searching technique is supported, sometimes the help page can give you a hand. Try to look for specialized search engines, although Altavista is one great search engine sometimes you could find what
you're looking for on a local search engine. I usually start my search by looking for a specialized search
engine and I often find what I want.