A Tier 2 page will have a link on the homepage, and a Tier 3 page will be linked from a Tier 2 page, not the homepage.
So, if you had a site about Las Vegas (about casinos, shows, restaurants, etc), a Tier 2 page could be "Las Vegas Hotels". A Tier 3 page would be something like "Cheap Las Vegas Hotels", "Expensive Las Vegas Hotels", Hard Rock Hotel Las Vegas" and so on.
Does that make sense?
If not, I'm sure a smarty pants will come along and pretty it up
