1. A system comprising: a hardware processor; and a storage device storing instructions that, when executed by the hardware processor, cause the hardware processor to: receive, for each of a plurality of publications, a set of comments provided for the publication; receive training data that specifies controversial terms; for each comment included in each set of comments, identify i) at least one controversial term included in the comment, or ii) at least one non-controversial term included in the comment, the identification being based on the training data; generate a controversy classifier that i) accepts, as input, a particular set of comments for a particular publication and ii) produces, as output and for each comment in the particular set of comments, data indicating a measure of controversy for the particular comment; identify a second set of comments for a second publication, the second set of comments selected from a plurality of comments associated with the second publication based upon time of entry of each comment in the second set of comments after publication of the second publication; provide each comment in the second set of comments to the controversy classifier as input; determine, using output from the controversy classifier, that each comment in the second set of comments is controversial or non-controversial; and determine, based on the determinations made for each comment in the second set of comments, that the second publication is controversial or non-controversial.