1. A computer-implemented method comprising: providing, by a computing system with which users are able to register as a first type of user, a second type of user, and as an administrator, a display of a particular hierarchy of nodes, in its entirety, to the administrator in a particular user interface, wherein some nodes in the particular hierarchy of nodes are parent nodes and other nodes in the particular hierarchy of nodes are child nodes to respective ones of the parent nodes; receiving, by the computing system, user input that interacts with the particular user interface to specify that: (i) a first collection of nodes in the particular hierarchy of nodes are to be displayed as selectable by only the first type of user, including at least one of the parent nodes and at least one of the child nodes, (ii) a second collection of nodes in the particular hierarchy of nodes are to be displayed as selectable by only the second type of user, including one or more of the parent nodes and one or more of the child nodes, and (iii) a third collection of nodes in the particular hierarchy of nodes are to be displayed as selectable by both the first type of user and the second type of user, including multiple of the parent nodes and multiple of the child nodes, and wherein a particular child node from the third collection of nodes is a child node to a certain parent node from the first collection of nodes; receiving, by the computing system, a first request by the first type of user to view a first display of the particular hierarchy of nodes on a first computing device, and in response sending, by the computing system, a first response that includes information for causing the first computing device to present the first display of the particular hierarchy of nodes, wherein the first display of the particular hierarchy of nodes: (i) presents the first collection of nodes that the administer specified to be displayed as selectable by only the first type of user, including the at least one of the parent nodes and the at least one of the child nodes, (ii) presents the third collection of nodes that the administrator specified to be displayed as selectable by both the first type of user and the second type of user, including the multiple of the parent nodes and the multiple of the child nodes, and (iii) omits from display the second collection of nodes that the administrator specified to be displayed as selectable by only the second type of user; and receiving, by the computing system, a second request by the second type of user to view a second display of the particular hierarchy of nodes on a second computing device and in response sending, by the computing system, a second response that includes information for causing the second computing device to present the second display of the particular hierarchy of nodes, wherein the second display of the particular hierarchy of nodes: (i) presents the second collection of nodes that the administrator specified to be displayed as selectable by only the second type user, including the one or more of the parent nodes and the one or more of the child nodes, (ii) presents the third collection of nodes that the administrator specified to be displayed as selectable by both the first type of user and the second type of user, including the multiple of the parent nodes and the multiple of the child nodes, and further including a presentation of the particular node that is the child node to the certain parent node, (iii) presents the certain parent node from the first collection of nodes that the administrator specified to be displayed as selectable by only the first type of user, (iv) omits nodes in the first collection of nodes other than the certain parent node from presentation, and (v) presents the particular node in a particular manner to indicate that the articular node is selectable, and presents the certain parent node in a manner that is different than the particular manner in order to indicate that the certain parent node is non-selectable.