1. A computer-implemented method comprising: accessing a plurality of social media content items authored by users of a social networking system; accessing programming information regarding an event of time based broadcast media aired during a segment of time; annotating the event with one or more metadata instances that has semantic information about the event, the annotating using an alignment function to estimate the likelihood that the event is described by one or more of the metadata instances; generating a set of mappings, each of the mappings generated by: performing a feature extraction process on a pair including the annotated event and one of the social media content items, the feature extraction process converting data to a common format by generating at least one content feature that identifies co-occurring textual information between the social media content item and one of the metadata instances of the annotated event, and generating a score for the content feature indicating whether the social media content item refers to the annotated event, using a feature specific sub-function for the content feature; and determining a level of social interest in the event based upon the set of mappings.
2. The computer-executed method of claim 1 wherein performing the feature extraction process further comprises: generating at least one geo-temporal feature referring to the difference in location at which the annotated event was generated from a location associated with the social media content item about the event; and generating a score for the geo-temporal feature indicating whether the social media content item refers to the annotated event, using a feature specific sub-function for the geo-temporal feature.