Hello Evelyn,
The reason why a Google search on your name shows you to be a member
of the British Association of Sexual and Relationship Therapy, but
does not show the same for the British Association of Counselling and
Psychotherapy lies in the way the two organizations lists their
members on their web sites.
The British Association of Sexual and Relationship Therapy has a
series of web pages, each listing one specific class of members in one
specific region. So, for example, the page for General Members in
London & Middlesex
is http://www.basrt.org.uk/content/show_therapists.asp?area=1&status=general
When you go to the Association's home page, there is a link
"therapists". Clicking on that opens a page with links to lists of
Supervisors, Accredited Members and General Members. Clicking on
General Members opens a list of links to the various regions, and
clicking on London & Middlesex takes you to the page that lists your
name. Therefore, there is a chain of three links between the home
page and the page that lists your name. Google, like other search
engines, works by following links from the home page, and then follows
other links it finds on the next set of pages and so on, so that it
gradually includes all the pages of a web site into its indexes.
Therefore, the London & Middlesex page, with all the information on it
including your name, has been indexed by Google.
The British Association of Counselling and Psychotherapy does not have
a set of web pages listing members. Instead, the details on members
are included in a database which can be searched in various ways:
http://www.bacp.co.uk/seeking_counsellor/seeking_counsellor_frameset2.htm
The results of each individual search are put together into something
called a "dynamic" web page. This is a page which is generated only in
response to a search; it is not present on the web site all the time.
The Google search engine is not able to crawl the database itself.
Therefore, when it crawls the BACP web site, it has no way of indexing
your name in relation to this site.
The only way a search engine would show you as a member of BACP would
be if you or someone else created a web site which included a page
with your name and details of your membership.
Database contents are part of what is known as the "Invisible Web", a
huge body of information that is present on the Internet but is not
indexed by search engines:
"Invisible web is the term used to describe the content that Search
Engines cannot access. It is estimated that the size of the invisible
web is 500 times bigger than the visible web. This is also known by
the term ‘deep web’. There are many reasons why Search Engines cannot
find all the information available on the Internet.
Search Engines cannot index Websites that require registration for
accessing their contents.
The database of a Search Engine is compiled automatically by spiders.
Spiders can find a page only if it is linked to any other page they
already ‘know’.
Search Engines may choose to exclude certain websites or webpages for
format reasons.
Search Engines do not immediately index new pages and new information
on old pages. It is estimated that Search Engines are out of currency
by 3-4 months.
Many websites store their information in a database and dynamically
create a webpage in response to a specific query. Search Engines
cannot index such dynamically created webpages." From Fathoming the
Deep by K.Sahasranaman
http://www.e-chemsolutions.com/Articles/SmartSearch16.htm
Search strategy: I already knew the answer to the question. However,
in order to find a citation to back up the answer, I searched Google
for: "search engines" "cannot index" database |
