1. A method of processing data, the method comprising; processing a data set to extract a hierarchy of topics; linking a portion of the data set to an appropriate topic of the hierarchy of topics, wherein the appropriate topic comprises one or more subtopics; training topic models for the appropriate topic and the one or more subtopics using the portion of the data set and a probabilistic learning technique; evaluating an accuracy of each topic model of the topic models; and identifying, using one or more processors, that the appropriate topic is most appropriate for textual data generated via a social networking service by examining the accuracy of each topic model.