Web Search Engines

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					Web Search Engines
                                                        Search engines designed for kids contain age-
                                                        appropriate content and use filtering programs that
                                                        eliminate much inappropriate content.

                                                        Issues Related to Search Engines
                                                        Most search engines limit the number of pages that
                                                        will be added to search engine databases. So not
                                                        every page of a Website may be searchable.

                                                        Most search engines only add the first 100 K of text
                                                        of each Web page to their database, then stop.
                                                        Therefore text at the end of long Web pages may
                                                        not be retrievable.

                                                        Search engines limit the size of their database by
                                                        deleting older pages when newer ones are located.
Web search engines are completely different than
Web indexes. They are very much like a keyword          Some search engines limit their searches to certain
search of your OPAC. Search engines retrieve            domains or Website portions that are considered to
information for you, by running software programs       be reliable and unique.
called „ bots‟. There are two types of search engine
bots; those that create and add to the search           Bots rely on links they‟ve discovered on Web pages
engine‟s database, and those that retrieve              to add to their database. If a Web page has no links
information from its database and arrange it            pointing to it, a search engine bot can‟t find it.
according to how relevant it is to your query.
                                                        There‟s a lag time between the time when a Web
Every search engine‟s bots are programmed               page is published and when a bot discovers and
differently. Some database bots are programmed to       indexes it. The other lag time is when a Web page
take every significant word from a Website (less        is included in a search engine database and when
those words that are non-searchable “stop words”),      it is re-visited and updated.
while other bots only add selected words or travel
only so deep down a Website‟s hierarchy before          Some search engines pre-program results for very
stopping and going elsewhere.                           popular queries. Some search engines program the
                                                        most popular/commonly selected Web pages to
Web search engine results are arranged by               appear near the top of the results list.
„relevance‟ rather organized by topic. Because
search engines are robot-built, they lack most of       Many search engines are biased toward text and
the “bells and whistles” of Web indexes. Sites aren‟t   away from images and other media. If a Web page
selected, nor are they evaluated and there is no        only contains an image map graphic there is
thesaurus to help bring similar terms together.         nothing for the search engine to index.
There is only one way to search - by keyword(s).
                                                        Even though search engines report that they
There are many different Web search engines.            retrieve thousands/millions of pages, only a few
Some are case-insensitive, others are case-             results (between 200 and 1,000) can actually be
sensitive. Each has unique features that work best      viewed. Results beyond that number limit can‟t be
for different searches and for varying information      displayed, unless you use other/additional search
needs. Search engines often retrieve way too much       terms.
information for the average library user.