The crawler or
Spider or a Bot refers to a special computer automated system which is
generally used by the search engines for indexing the relevant sites. The crawler
crawls over the different kinds of web pages and copies the content and stores
them. When a user looks for a specific keyword then the crawler looks into the
storage and provides the search engine with the relevant information and that
too without taking too much time. The crawler mostly goes through the text of
the site only and is able to capture that and store it in its own database. It
also crawls over the website that it has covered in the past and checks it for
new developments and changes and then acknowledges the same. It is very useful
for the search engines and for SEO purpose as it makes the search engine’s work
faster and more efficient.
Apart from the
search engine crawlers there are others kinds of BOT or crawlers also which may
work on an altogether different set of instruction. For instance, the crawlers
may be used someone to simply get a list of email addresses which are then used
for spamming. Until and unless the website is not crawled it may not show up in
the search engines result and this is why it is considered to be very
important.