Each search engine gets its listing
from a variety of sources. This chart shows where the results
come from...
SEARCH
ENGINE
TYPE
OF MAIN RESULTS
PROVIDER
OF MAIN RESULTS
PAID
RESULTS
DIRECTORY
&/OR BACKUP
AllTheWeb.com(FAST)
Crawler
AllTheWeb.com(FAST)
Overture (and late 2002
Lycos)
N/A
AltaVista
Crawler
AltaVista
Overture
LookSmart
AOL Search UK
Crawler
Google
Overture
Open Directory
Ask Jeeves UK
Crawler
Teoma
Espotting
Ask Jeeves
Google
Crawler
Google
Google
Open Directory
HotBot UK
Clickthrough
AllTheWeb.com(FAST)
N/A
Open Directory &
backup from Inktomi
LookSmart UK
Human
LookSmart
LookSmart
Google & Inktomi
Lycos
Crawler
AllTheWeb.com(FAST)
Overture (and late 2002
Lycos)
Open Directory
MSN Search
Human
LookSmart
Overture
Backup from Inktomi
Overture
Paid
Overture
Overture
Backup from Inktomi
Teoma
Crawler
Teoma
Google
N/A
Yahoo! UK
Crawler
Google
Espotting
Yahoo!
While search engines
display results from many different sources, usually the
results from one particular source will be dominant. These
are considered to be the main results for that search engine.
There are specific ways that engines can find their results:
CRAWLER - the main results are compiled
by having crawled the web.
HUMAN - the main results come from
listings complied by human editors.
PAID - the main results come form paid
listings.
CLICKTHROUGH - the main results come
from measuring what people click on.
Along with the main results,
most major engines offer some paid listings for each search.
These would normally be presented as 'sponsored links' or
'recommended sites'. Finally, for search engines where the
main results coem from human work, it's common for them
to have a 'backup' or 'fallthrough' partnership with a crawler-based
search engine.
