1. A method comprising, by one or more computing devices: accessing, by the one or more computing devices, a plurality of communications authored by one or more users of an online social network, each communication being associated with a particular content item and comprising a text of the communication; extracting, for each of the plurality of communications, one or more quotations from the text of the communication; determining, for each extracted quotation, one or more partitions of the quotation; grouping, by the one or more computing devices, the extracted quotations into one or more clusters based on a respective degree of similarity among their respective one or more partitions; calculating, by the one or more computing devices, a cluster-score for each cluster based on a frequency of occurrence of one or more partitions of one or more quotations in the cluster in communications associated with the particular content item; and generating, by the one or more computing devices, a quotations-module comprising one or more representative quotations, each representative quotation being a quotation from a cluster having a cluster-score greater than a threshold cluster-score.