1. A method comprising: accessing a plurality of initial content items, each initial content item associated with a geographic location; determining a selected zoom level for a map interface for displaying one or more of the initial content items thereon; determining a threshold distance for aggregating the initial content items based on the determined zoom level for the map interface; performing an aggregation process to generate a set of aggregated content items from the initial content items, the aggregation process comprising: selecting a pair of content items, from the sets of initial and aggregated content items, for which the geographic locations have a shortest distance therebetween, if the distance between the geographic locations of the selected pair of content items is within a threshold distance, combining the selected pair of content items into a new aggregated content item, and determining a geographic location for the new aggregated content item as a weighted average of the geographic locations of the initial content items associated with the new aggregated content item; repeating the aggregation process until the shortest distance between a pair of content items, from the sets of initial and aggregated content items, is larger than the threshold distance; and sending for display to a viewing user the map interface with the sets of initial and aggregated content items displayed thereon at their corresponding geographic locations.