1. A computer-implemented method for identifying related digital content items in a plurality of digital content items V comprising digital content item (V 1 ,. .. V n ), the method comprising: for a plurality of pairs of digital content items (V i , V j ) in the plurality of digital content items V, accessing a count C i,j of a number of positive user interactions of each of a plurality of users with digital content item V i which co-occurred within a locality of time with positive user interactions of the user with digital content item V j included in each pair of digital content items (V i , V j ); for at least one digital content item V i included in the plurality of pairs of digital content items (V i , V j ), ranking the digital content items V j according to the counts C i,j ; and for the at least one digital content item V i , identifying a set R i of related digital content items from the ranked digital content items V j based on the ranked counts C i,j .