An electronic lockbox system allows both sales agents and sales prospects to communicate either with the lockbox, or with the central clearinghouse computer. Contextual data then is provided to the sales prospect while the prospect is visiting a specific property that is the site of a lockbox installation. Both the agent and the prospect use smart devices, such as smart phones, that have both wide area network capability and low power radio capability. In other situations, contextual data can be sent to a user having a smart device, in which that contextual data pertains to at least one human occupant of the specific property where that lockbox has been installed, which can be useful where a medical caregiver arrives to visit a human occupant of a specific property that is protected by the electronic lockbox.