6.2 Demonstrate knowledge of search logic, search engines and features of the Internet

Table of Contents

1. Introduction
   1. Boolean logic
   2. The Boolean operators
   3. Logic diagrams: the AND operator
   4. Logic Diagrams: the OR operator
   5. Logic Diagrams: the NOT operator
   6. Using multiple Boolean operators
   7. Constructing precise Boolean searches
   8. Search engine assumptions
   9. Advanced search facility
   10. Advanced searching on Yahoo
   11. Other points on Boolean searching ...
2. Truncation and wildcards
3. Grammar of the Internet
4. Search engine operation
5. Ownership of the web
6. Dark internet and the invisible web

Search engine assumptions

If the search engine makes certain assumptions about what you mean when you enter search terms in a particular way. You must understand the implications of these assumptions.

Basically when you enter more than one term in the search box, the search engine turns this into a Boolean search. The two possibilities are that the engine defaults to an AND or an OR.

Most of the common search engines default to AND. So putting in carriage clock should return results with both words included. Of course the words may appear in any order and not necessarily next to one another.

Google allows the use of a minus sign (-) to use the NOT operator. Thus to create the Boolean search expression sixties pop NOT beatles, you would enter sixties pop -beatles (Note: You must not leave a space between the minus and the search term which you wish to exclude.)

Google assumes that some common words and numbers are never included in the search. Thus if such a word is particularly required, it must be prefaced by a plus (+) sign. This is essentially the Boolean AND operator.

Using + and - in this way is not as predictable as you might expect in many search situations. We recommend that they should be used only when there is no alternative. You can find out more here http://www.google.co.uk/help/basics.html

Let's look now at the Advanced search facility ...