Topic and time based media affinity estimation

A non-transitory computer-readable storage medium comprising instructions for recommending a time-based media event that when executed cause a system of one or more computers to perform operations to:

• receive a plurality of content items authored by users of a social networking system;
• receive data representing a plurality of time-based media events, each time-based media event having a respective association with at least one topic of a plurality of topics;
• generate mappings between the content items and the plurality of topics;
• determine a first affinity score between a first population of users, the first population including only users who authored content items mapped to a first topic of the plurality of topics, and a second population of users, the second population including only users who authored content items mapped to a second topic by the mappings, the first population and the second population each being a respective population of users of the social networking system;
• and
• recommend a time-based media event to a first user based on the affinity score meeting a threshold, wherein the recommended time-based media event is associated with the second topic and is not associated with the first topic, and the first user is a user of the social networking system having authored a content item mapped to the first topic.

A system comprising one or more computers and a memory storing computer program instructions for recommending time-based media events that when executed by the one or more computers causes the one or more computers to perform operations to:

• receive a plurality of content items authored by users of a social networking system;
• receive data representing a plurality of time-based media events, each time-based media event having a respective association with at least one topic of a plurality of topics;
• generate mappings between the content items and the plurality of topics;
• determine a first affinity score between a first population of users, the first population including only users who authored content items mapped to a first topic of the plurality of topics and a second population of users, the second population including only users who authored content items mapped to a second topic by the mappings, the first population and the second population each being a respective population of users of the social networking system;
• and
• recommend a time-based media event to a first user based on the affinity score meeting a threshold, wherein the recommended time-based media event is associated with the second topic and is not associated with the first topic, and the first user is a user of the social networking system who authored a content item mapped to the first topic.