With billions of pages, you could spend a lifetime surfing the
Web, following links from one page to another. Amusing perhaps, but not
very efficient if you're seeking some specific information. So where do you start? Searching the Web requires part skill, part luck
and a little bit of art. Fortunately, a number of free online resources
help with the hunt.
You've probably heard of search engines such as Yahoo!, Google, and Bing.
There are literally dozens of these tools to help you locate what you're
looking for. The trick is understanding how they work so you can use
the right one for the job.
Types of Search Engines
Search engines break down into two types: directories and
indexes. Directories, such as Yahoo!,
are good at identifying general information. Like a card catalog in a
library, they classify websites into categories, such as accounting
firms, English universities and natural history museums. The results of
your search will be a list of websites related to your search term. For
instance, if you are looking for natural history museums, you might use a directory to find it.
But what if you want specific information, such as biographical information
about Leonardo da Vinci? Web indexes are the way to go, because they search
all the contents of a website. Indexes use software programs called spiders
and robots that scour the Internet, analyzing billions of web pages, newsgroup and blog postings, and indexing all of the words. Some also index audio, video and images.
Indexes like Google and Bing identify the text on individual pages of a website that match your search criteria, even
if the site itself has nothing to do with what you are looking for. You
can often find unexpected gems of information this way, but be prepared
to wade through a lot of irrelevant information too.
Search results are usually ranked in order of relevancy--the number of times
your search term appears in a document--or how closely the document appears
to match a concept you have entered. This is a much more thorough way
to locate what you want.
Cable Cars to the Stars
Let's perform an online search using three popular search engines--Yahoo!,
Google, and Ask--so you can see how they work and how you can develop
an efficient search strategy.
Here's the challenge: You're planning a trip to San Francisco and you've
always wanted to ride a cable car. Do they operate in January and if so, what's the schedule?
we'll try Yahoo! One trick when searching is to narrow your focus. Entering
"San Francisco" in the search box results in over millions of pages of information
related to the City by the Bay! Entering "cable cars" also results
in millions of pages, many of which have nothing to do with San Francisco. By combining
the terms ("San Francisco cable cars") we've narrowed the search greatly. Now you have to visit
each page to see if there's any information about cable car schedules. Fortunately, the first three sites listed all contain information pertinent to our search.