1. A method comprising: identifying a new media clip provided by a first user; providing a feature vector associated with the new media clip to a first classifier, wherein the feature vector associated with the new media clip includes a plurality of values representing one or more features extracted from content of the new media clip, wherein the first classifier was trained using a plurality of features vectors of a plurality of existing media clips to produce suggested semantic tags for respective existing media clips; obtaining, by a computer system, a first set of semantic tags for the new media clip from the first classifier; providing, by the computer system, the first set of semantic tags for the new media clip to a second classifier that was trained using input-output pairs, wherein an input of each input-output pair includes a subset of the suggested semantic tags that was previously produced by the first classifier and suggested to a second user for one of the respective existing clips, and wherein an output of the input-output pair includes one or more suggested semantic tags selected by the second user from the subset of the suggested semantic tags for the one of the respective existing clips; obtaining, by the computer system, a second set of semantic tags for the new media clip from the second classifier; and suggesting to the first user, by the computer system, the second set of semantic tags for the new media clip.