1. A machine-implemented method comprising: analyzing digital information viewed as a labeled graph, including nodes and edges, based on a flow of authority among the nodes along the edges, the flow of authority being derived at least in part from different authority transfer rates assigned to the edges based on edge type schema information, wherein the authority transfer rates depend on semantic meanings of edge types; and generating, in response to a query including at least one keyword, a keyword-specific ranking of the nodes based on a result of the analyzing.