4. The system of claim 1 , wherein the one or more modules are configured to store instructions, which when executed by at least one of the one or more processors, cause the system to further perform an operation to determine a location within a user interface on which to place a reference for the digital content based on one or more of first value, the second value, and a third value that indicates a relationship between the source and the digital content.
1. A system comprising: one or more processors; and one or more modules configured to store instructions, which when executed by at least one of the one or more processors, cause the system to perform operations to: detect a recommendation, by a recommendation source to a receiver of the recommendation, of digital content hosted by a digital content host, wherein the digital content host is distinct from the recommendation source and the recommendation of the digital content is associated with a topic, detect a first value that relates the recommendation source to the receiver of the recommendation specifically for prior recommendations of digital content, from a plurality of digital content hosts, that is associated with the topic, and calculate a second value associated with the digital content based on the first value.