A website is like a train station, it has visitors that come and go through it to get around on the Internet. Think about it, whenever you visit a website, you click on a link that takes you to the next page that has the information on it your desire. Eventually if you click long enough you get to a web "station" that allows you to visit any website in the world.

This would in essence be a web portal, like Yahoo or AOL has. For these big web "stations" you can get to anywhere around the world. This is what the search engine spiders have to do; they can’t “Google” a web site like you and me. They rely on link to web pages, and eventually run into a huge web station that they constantly come back to for references.