Lets say there is a regional directory for Boston cars. One Subpage is about Mercedes. This subpage ranks very well for "Mercedes Boston". On the subpage there are small texts+backlinks to Mercedes dealers in Boston. It is not a "dead directory" but has real visitors. Therefore the backlinks are valuable because they bring real traffic! But what is the worth of those backlinks for SEO? Lets say on this subpage we have links to 10 local car dealers. For google it should be pretty obvious that those are paid links. Do they still have value for SEO? Remember, the linking subpage ranks very well for the keyword itself!