Links are managed and units of information are linked based on a list having identifiers placed in a hierarchical order relative to other identifiers, the identifiers for identifying the units of information. Lists are stored and examined to determine the hierarchical order of the identifiers relative to the other identifiers, and a unit of information is linked to at least one other unit of information based on a relative hierarchical order between an identifier identifying the unit of information and another identifier identifying at least one other unit of information.