6. The method of claim 2 , wherein for each node within at least a portion of the nodes, the input is received from the particular user when the particular user accepts a friend request from an entity represented by the node, or the particular user sends a friend request to the entity represented by the node.
2. The method of claim 1 , wherein the importance rating obtained from the particular user for each of the plurality of nodes other than the particular node is obtained by receiving input from the particular user.