A method, comprising: transmitting, from a first computing device to a computer system, a request to create a reminder, wherein the computer system is configured to, in response to receiving the request: notify a second computing device of the reminder; receive, from the second computing device, confirmation that the second computing device will allow proximity communications with the first computing device; generate a reminder identifier associated with the reminder; and provide to the first computing device and the second computing device the reminder identifier, wherein the first computing device and the second computing device are configured to store the reminder identifier in response to receiving the reminder identifier; identifying, by the first computing device, a geographic proximity of the second computing device by detecting, by the first computing device, a broadcast from the second computing device of the reminder identifier, the broadcast using a short-range communication protocol having a maximum range of less than about one hundred meters; establishing, by the first computing device, direct short-range communications with the second computing device, the first computing device and the second computing device being able to communicate with one another using a short-range communication protocol; receiving, by the first computing device, an indication that the first computing device shares the reminder identifier with the second computing device; and receiving, by the first computing device, information relevant to the first computing device regarding the second computing device based on the shared reminder identifier. transmitting, from a first computing device to a computer system, a request to create a reminder, wherein the computer system is configured to, in response to receiving the request: notify a second computing device of the reminder; receive, from the second computing device, confirmation that the second computing device will allow proximity communications with the first computing device; generate a reminder identifier associated with the reminder; and provide to the first computing device and the second computing device the reminder identifier, wherein the first computing device and the second computing device are configured to store the reminder identifier in response to receiving the reminder identifier; notify a second computing device of the reminder; receive, from the second computing device, confirmation that the second computing device will allow proximity communications with the first computing device; generate a reminder identifier associated with the reminder; and provide to the first computing device and the second computing device the reminder identifier, wherein the first computing device and the second computing device are configured to store the reminder identifier in response to receiving the reminder identifier; identifying, by the first computing device, a geographic proximity of the second computing device by detecting, by the first computing device, a broadcast from the second computing device of the reminder identifier, the broadcast using a short-range communication protocol having a maximum range of less than about one hundred meters; establishing, by the first computing device, direct short-range communications with the second computing device, the first computing device and the second computing device being able to communicate with one another using a short-range communication protocol; receiving, by the first computing device, an indication that the first computing device shares the reminder identifier with the second computing device; and receiving, by the first computing device, information relevant to the first computing device regarding the second computing device based on the shared reminder identifier.