1. A computer-implemented method for active tagging, comprising: performed by one or more processors executing computer-readable instructions: selecting a file from a data set stored in a memory based at least in part on an informativeness measure of the file, wherein the informativeness measure is based at least in part on at least one of a citation measure, an ambiguity measure, or a diversity measure; providing the file to a client device for manual tagging by a user of the client device; receiving a manually tagged file from the user of the client device; storing the manually tagged file in the data set; predicting a tag for another file based at least in part on the manually tagged file to create another tagged file in the data set that is distinct from the manually tagged file in the data set; and storing the other tagged file in the data set.