1. A computer-executed method for associating social media content items with a time-based media event, the method comprising: accessing from a social networking system a plurality of candidate social media content items authored by users of the social networking system; for each of the candidate social media content items, determining a confidence score indicative of a probability that the candidate social media content item is relevant to the event; aligning with the event, based on their respective confidence scores, a subset of the plurality of the social media content items; and collecting in a data store the alignments between the event and the subset of the plurality of the social media content items.