1. A method of ranking nodes in a graph, comprising: receiving a graph comprising a plurality of nodes and edges at a node ranker of a computer device; selecting a subset of the nodes of the graph using a node selector; generating a random walk for each of the nodes in the subset of the nodes of the graph using a random walk generator, each random walk comprising nodes reachable from a selected node in the subset of the nodes by following edges of the graph starting from the selected node; and appending the generated random walks together to create a single random walk using the random walk generator, the single random walk being longer than each random walk for each of the nodes in the subset of the nodes of the graph.