Googlebot

Googlebot is the name of the search engine spider for Google. Googlebot will visit sites which have been submitted to the index every once in a while (in my experience this spider visits once a month or so) to update it's index.

Googlebot obeys the contents of your Robots.Txt file as well as the Robots Metatag. Google has also created a special version of the robots metatag to control indexing of just Googlebot. Like most search engine spiders, Googlebot follows HREF tags. It also follows SRC tags.