In one embodiment, a method includes receiving a message comprising status data from a second computing device, determining that a geographic area is a hotspot based at least on the status data, where mobile users in a hotspot have a high probability of accessing an application on their mobile computing devices, and sending an indication that the geographic area is a hotspot to a third-party computing device, where the indication is used by the third-party computing device to determine a value for delivery of content to computing devices associated with the geographic area.