1. A computer-implemented method for generating a social sketch corresponding to a time period in response to a request, the method comprising: obtaining social communications from a social networking service, the social communications including social communications generated during a first time period; filtering obtained social communications according to the first time period such that the filtered social communications correspond to the social communications generated during the first time period; clustering the filtered social communications according to the subject matter of the social communications to generate a plurality of clusters of filtered social communications, each cluster corresponding to a topic; identifying a set of clusters of the plurality of clusters of social communications, each of the clusters of the set of the plurality of clusters of social communications being an identified cluster; for each identified cluster: extracting a topic from the identified cluster according to the subject matter of the social communications of the identified cluster; identifying a non-expert set of high-quality communications from the identified cluster, the non-expert set of high-quality communications corresponding to social communications of non-experts on the topic of the identified cluster; identifying an expert set of high-quality communications from the identified cluster, the expert set of high-quality communications corresponding to social communications of experts on the topic of the identified cluster; wherein the topic, the non-expert set of high-quality communications, and the expert set of high-quality communications comprise a cluster set of the identified cluster; and storing the cluster sets of each of the identified clusters as the social sketch corresponding to the identified time period.