Welcome — to the PCMEE Production ® (pending)
Directory (Search Engines) section of the site, the acronym — PCMEE represents: Personal Computers (P.C) —
Modems (Network Systems / Internet Related Systems / Sites) — Electro-Mechanics (Automotive Electrical Systems)
And Electronics (Electronic Systems), additionally — Business related clerical services
(Resum'e / Cover-Letter / Documentation) is also among the diverse technical services PCMEE Production provides
to our customers.
A search engine is an information retrieval system designed to help find information stored on a computer system,
such as on the World Wide Web, inside a corporate or proprietary network,
or in a personal computer. The search engine allows one to ask for content meeting specific criteria
(typically those containing a given word or phrase) and retrieves a list of items that match those criteria.
This list is often sorted with respect to some measure of relevance of the results.
Search engines use regularly updated indexes to operate quickly and efficiently.
Without further qualification, search engine usually refers to a Web search engine,
which searches for information on the public Web. Other kinds of search engine are
enterprise search engines, which search on intranets, personal search engines,
and mobile search engines. Different selection and relevance criteria may apply
in different environments, or for different uses.
Some search engines also mine data available in newsgroups, databases, or open directories.
Unlike Web directories, which are maintained by human editors, search engines operate algorithmically
or are a mixture of algorithmic and human input.
For directory-based search services, the primary frame of reference is the subject matter.
The site listings are compiled and reviewed manually.
For example, Yahoo, one of the best known Internet Directory, dedicates staff to review and categorize
site suggestions and then adds them to a specific directories on Yahoo. The directory structure
is hierarchical and starts with a general subject heading such as dentistry.
Keywords found within a web sites individual pages, are just that: key words. Nothing magical.
They are the words that potential visitors might enter into a search engine
that could lead them to your site.
For example, to find a particular music site, I might enter the search terms, "blues music."
On Google, that returns about 796,000 links. But let's say that I'm interested
in blues music from the Mississippi Delta. Then I would add the word "delta" to my search:
"blues music", delta (the quotes keep the words together). That narrows it down to 30,500 links.
That's still a lot of links but many of them probably aren't relevant to what I want and it's
a little more manageable than 796,000. Of course, the search could be further refined.
The search engine returns these particular pages because they have the words blues music and delta on them
(or in the anchor text of links pointing to them, see below); those are the keywords, in this case.
If you have a web site about blues music then you need to add those words somewhere on your web pages
so they can be found by people who want to know more about blues music in the delta. You might also
be able to have them included in the anchor links pointing to your site. But do you just add the
keywords at random on the page or maybe within a comment tag?
It doesn't quite work that way. The algorithms used by the search engines have become
very sophisticated and would pick that up right away.
Instead, you should have content that contains the keywords, such as articles about the
delta blues, albums and songs with the words in their titles and song lyrics containing
the words, however, you don't want the page to just contain those keywords or be heavily
weighted in their content. According to Google's standards, no more than 2% of the words
on a page should be actual targeted keywords. A general rule of thumb is 2%-8%.
It's called "keyword density" and refers to the percentage of keywords contained within
the total number of indexable words on a web page.
Generally, keywords are put in the title and meta tag. They should also have prominence within the page,
i.e.at the beginning of the web page and at or near the beginning of a paragraph or a sentence.
There are places on the web to help determine good keywords. Some internet
marketing specialists provide special copywriting services just for keyword placement,
but that may be going a bit overboard.
A meta-search engine is a search engine that sends user requests to several other search engines
and or databases and returns the results from each one.
Meta search enables users to enter search criteria once and access several search engines simultaneously.
Since it is hard to catalogue the entire web, the idea is that by searching multiple search engines
you are able to search more of the web in less time and do it with only one click.
The ease of use and high probability of finding the desired page(s) make metasearch engines popular
with those who are willing to weed through the lists of irrelevant 'matches'. Another use is to get
at least some results when no result had been obtained with traditional search engines.
Query processing has seven possible steps, though a system can cut these steps short
and proceed to match the query to the inverted file at any of a number of places
during the processing. Document processing shares many steps with query processing.
More steps and more documents make the process more expensive for processing in
terms of computational resources and responsiveness.
However, the longer the wait for results, the higher the quality of results.
Thus, search system designers must choose what is most important to their users —
time or quality. Publicly available search engines usually choose time over very
high quality, having too many documents to search against.
There are three broad categories that cover most web search queries: Informational queries –
Queries that cover a broad topic (e.g., colorado or trucks) for which there may
be thousands of relevant results.
Navigational queries – Queries that seek a single website or web page of a single
entity (e.g., youtube or delta airlines).
Transactional queries – Queries that reflect the intent of the user to perform a particular action,
like purchasing a car or downloading a screen saver.
Search engines often support a forth type of query that is used far less frequently:
Connectivity queries – Queries that report on the connectivity of the indexed web graph (e.g.,
Which links point to this URL?, and How many pages are indexed from this domain name?).
Search engines are the key to finding specific information on the vast expanse of the World Wide Web.
Without sophisticated search engines, it would be virtually impossible to locate
anything on the Web without knowing a specific URL.
The search engines considered Special are used to find specific information,
when people use the term search engine in relation to the Web, they are usually referring to
the actual search forms that searches through databases of HTML documents,
initially gathered by a robot.
There are basically three types of search engines: Those that are powered by
robots (called crawlers; ants or spiders) and those that are powered by human
submissions; and those that are a hybrid of the two.
Super Search Engines search via multiple resources to achieve desired results
e.g. magazines, journals, reports and documents in a single search, combining materials
from many different databases into one powerful search.
Weighted search engines rely on a link popularity score, wich refers to the total number
of external sites that link to yours. Link importance is closely related to link popularity,
but with a twist. It looks at the type of external link and assigns higher scores to high quality links.
Link importance helps filter out the spammers who set up dozens of free sites and then
link their bogus sites to the main Web site. Spamming is such a problem that some search
engines don't count free Web sites at all in their link popularity scores.
Some of the more complex search engine algorithms combine link popularity with
link importance and use it to assign a weighted link popularity score.
The weighted score looks at two things: the number of sites linked and the relative
importance of those sites. For instance, if CNN links to your site, that single
link might count a lot more than 20 links from your friends' personal Web pages.
Surfy.Com (A Meta-Search Directory)
