10. The media of claim 9 , wherein the software operable when executed to determine the confidence score comprises software operable when executed to: determine a probability that a random walk starting at the first one of the user nodes will end at the first one of the concept nodes.
10. The media of claim 9 , wherein the software operable when executed to determine the confidence score comprises software operable when executed to: determine a probability that a random walk starting at the first one of the user nodes will end at the first one of the concept nodes. 11. The media of claim 10 , wherein the software operable when executed to determine the probability that the random walk starting at the first one of the user nodes will end at the first one of the concept nodes comprises software operable when executed to: determine, for each particular edge in the random walk, the probability of taking the particular edge during the random walk, based on the affinity score associated with the particular edge.