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Webwatch
June 2003
As included in the last issue of The Platelet, mention was made about how to search for a word in just one site, using the syntax child site:www.itpsupport.org.uk in Google.
Perhaps some more information on searching the internet may be of help.
There are two kinds of search engine, one that relies on computers to
index words, the other that relies on humans to make an index of websites.
The second kind is declining in use, they require lots of people to create
and maintain the index. Examples of these are Open Directory or LookSmart.
Of the first type, engines such as Google use computers to look into (or
spider) websites, making a gigantic index of the words it finds. It does
not "understand" about subjects. For example, a recent search
for ANA and ITP resulted in 7,500 hits, the first being a link to a site
that said "On behalf of IT Power, I send my sincere condolences to
Ana"! The software was just doing what it was told, it found "Ana"
and ITPower! Had I known that in the context of ITP, ANA stands for antinuclear
antibodies and had searched for "antinuclear antibodies itp",
the result would have been less than 200 largely relevant hits. The lesson
here is that a little knowledge of what you are searching for is very
useful. Successful searches come from using subject or language skills
than "computer knowledge".
Search engines vary all the time, currently the popularity of the top ones are approximately Google with 30% of users, Yahoo 29%, MSN, 27%, AoL 10%, with Lycos, Looksmart, Ask Jeeves etc. making up the balance. The oldest engine, Yahoo, used humans to build their index until recently, when it linked up with Google. Search engines also use each other's indexes to find results and many use systems that do not have a public face such as Inktomi. This is a huge index of websites only available to other search engines. It means that means the majority of the people searching the internet are actually searching essentially the same index of information. Naturally, searching for "itp support" in Google, Yahoo or MSN, the Association website comes out at the top!
Sometimes, the results of a search seems to give information totally different from what was searched for. Travel companies and hotel reservation companies seem to be the worst at this, but how does it happen? As search engines simply look at words on the site, especially words near the top of a page, unscrupulous people have been known to put all sorts of commonly searched for words in the website but use the same text colour as the background so you cannot see them! The search engines dutifully add these words to their index. Sometimes a large area that appears blank actually contain these words. Avoid such sites, they have an ulterior motive for their web presence.
As an example of effective searching, you may like to set yourself the task of finding out what substances in chocolate may be related to making some people feel unwell. A search for "chocolate ingredients" will reward you with over half a million recipes! A search for "chocolate chemical ingredients" will give nearly 30,000 hits, too many to be useful. Adding "migraine" to the search gave 1,300 hits which is better but still too many. Reading some of the first sites from this list however, gave a clue to what to search for, such as phenylethylamine. Searching for "chocolate chemical ingredients migraine phenylethylamine" gave about 70 very useful hits.
A very detailed account of how search engines work etc. can be found on www.searchenginewatch.com
Happy surfing
Howard