Search Engine spider
A Search Engine spider, sometimes called a
web crawler, is how search engines gather their results. Search Engines
use Spiders to crawl through websites and extract relevant information
in regards to the word or phrase that the user has searched for. Search
Engines use this technique to gain up to date information in their
results. Spiders usually make duplicate copies of every page that has
been visited; this is for later processing which is done by the search
engine, who will then index the downloaded pages which will enable the
fast searches that we all take for granted.
Due to the vast size of the internet, and with websites being created
and updated constantly, the spiders are always crawling through the
internet. Yet, with such a massive collection of websites, it is more
than likely that by the time a spider has finished crawling and
downloading the final pages from a website, it is more than probable
that those websites have had pages added, edited or even deleted.
Spiders have other uses too, including; automatic maintenance on servers
or websites, with jobs including link checking and HTML code validation.
Spiders are also used in black hat e-mail harvesting and this is usually
for spamming purposes. Spiders are an effective way of easily carrying
out what would be a tedious chore for any human.
Without spiders crawling through the most relevant web pages, the search
engines would take a lot longer to retrieve the results you have
searched for. As a Spider downloads a small amount of website pages,
Search engines realise that their users want to have the most relative
results and not just random websites. The most relevant web sites are
found by prioritising them based on factors such as link popularity, its
content quality and other factors to be later developed in the manual
series.
The spiders are an important way of quickly gathering, storing and
searching through information to enable us, as search engine users, to
benefit from fast paced results.
