1. A non-transitory computer readable medium storing a computer program executable by a processor, the computer program producing a user interface of a social interest estimation system, the user interface comprising: a media display area for displaying a media event from a time-based media source, the media event having a time of occurrence; a social media display area, visually distinguished from and concurrently displayed with the media display area, for displaying a plurality of relevant social media content items, the social media content items: broadcasted by a social media source, the social media source independent from the time-based media source; and determined to be relevant to the displayed media event based on a relationship between the time of occurrence and a time of authorship of each of the plurality of social media content items; and a social interest heat map area, visually distinguished from and concurrently displayed with the media display area and the social media display area, for displaying a social interest heat map showing levels of social interest for a plurality of media events from the time-based media source based on a number of social media content items determined to be relevant to each of the media events.