Google Basics
Generally speaking, there are two types of search engines on the Internet. The first is called the searchable subject index. This kind of search engine searches only the titles and descriptions of sites, and doesn’t search individual pages. Yahoo! is a searchable subject index. Then there’s the full-text search engine, which uses computerized “spiders” to index millions, sometimes billions, of pages. These pages can be searched by title or content, allowing for much narrower searches than searchable subject index. Google is a full-text search engine.
Whenever you search for more than one keyword at a time, a search
engine has a default method of how to handle that keyword. Will the
engine search for both keywords or for either keyword? The answer is
called a Boolean default; search engines can default to Boolean
AND (it’ll search for both
keywords) or Boolean OR (it’ll
search for either keyword). Of course, even if a search engine
defaults to searching for both keywords (AND) you
can usually give it a special command to instruct it to search for
either keyword (OR). But the engine has to know
what to do if you don’t give it instructions.
Basic Boolean
Google’s Boolean default is AND; that
means if you enter query words without modifiers, Google will search
for all of them. If you search for:
snowblower Honda "Green Bay"
Google will search for all the words. If you want to specify that either word
is acceptable, you put an OR between each item:
snowblower OR snowmobile OR ...
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