“Just looking around.” — Those who have never said those words have never been to a clothing store. The “just thinking” visitors are the nightmare of an e-merchant. The aim is to make them purchase the product but you are not there in person to assist them, to encourage them. On the other hand, this does not mean that you cannot push them with other tools.
Link building in search engine optimization has a role just like the relationship network in your social life. How "important" person you are is not only influenced by how many people you know. It is also affected by how many people have good opinion about you, if other "important" people know you or refer to you.