Transcript 7_hSearchEngines

HIGHER COMPUTER NETWORKING
Lesson 7 Search engines
Description of search engine methods
McLean 2006
1
HIGHER COMPUTER NETWORKING
What You Should Know About Search Engines
Search Engines
A Search Engine is a web site which contains an indexed
database of information about a large number of web pages.
Crawler Based
These search engines use programs called spiders which crawl
through the web looking for pages which are linked to sites
already stored in it’s database. When a new page is found it’s
Meta Tags are added to the database. Google is an example of
a crawler based search engine.
Directories
These search engines rely on humans to regularly update and
add to their databases. When a user query is entered the search
engine only looks for matches in the description submitted.
Yahoo is an example of this type of search engine.
McLean 2006
2
HIGHER COMPUTER NETWORKING
What You Should Know About Search Engines
Meta Tags
These are HTML tags placed in the header section of the page.
Meta tags are not visible to the user but are used by search
engines to index web pages.
Meta Search Engines
These search engines pass user queries to several other search
engines then collate and summarise the results. This means that,
theoretically, these search engine programs should give the user
the best results from their query.
‘Ask’ and ‘Metacrawler’ are examples of meta search engines.
McLean 2006
3