We consider disruption tolerant networks (DTN) in which mobile nodes are wireless devices carried by humans. Mobile users subscribe to a content distribution service and share their contents if they share the same interests. We assume that we know the probability of the event that a node subscribes to a content and the distribution of inter-contact times. We investigate both closed-form expressions and asymptotic approximations of the expected message delay and the number of copies of the message at the time the message is delivered. The analytical results are validated through simulation under a number of mobility models (the random waypoint, random direction and the random walker mobility models).