the spiders/bots trawl through each page of ya site and index the pages it goes through into the search engine
ya want the spiders on ya site as then you know the site is getting indexed in google and people can find ya through searches, which brings ya visitors
if you get linked from a few sites then google will find ya and index ya site, it can sometimes take a good few months for you to start seeing the results in google etc
the spiders/bots trawl through each page of ya site and index the pages it goes through into the search engine
ya want the spiders on ya site as then you know the site is getting indexed in google and people can find ya through searches, which brings ya visitors
if you get linked from a few sites then google will find ya and index ya site, it can sometimes take a good few months for you to start seeing the results in google etc