Methods, and systems, including computer programs encoded on computer-readable storage mediums, including a method for adjusting content delivery based on user submissions. The method includes analyzing user submissions comprising photographs, the analyzing comprising: for each of the user submissions: identifying a time the user submission occurred; identifying objects represented in the photograph; determining a subject matter of the user submission based at least in part on the objects; determining a geographic location associated with the subject matter of the user submission; determining clusters of the user submissions, each user submission in a particular cluster being similar to each other user submission in the particular cluster based on the times the user submissions occurred, the subject matters of the user submissions, and the geographic locations associated with the user submissions; and adjusting content delivery to members of a network based on the determination of one or more of the clusters.