A wireless communication system comprising: a wireless device (104; 1230) associated with a user of a social networking system; and a base station (102, 400) comprising: a network connection configured to receive information from the social networking system; and a radio frequency transceiver configured to generate, using a processor of the base station, an RF signal and communicate with the wireless device using backscatter communication and to transmit data to the wireless device (104, 1230) using an RF signal, wherein: the data transmitted to the wireless device (104, 1230) comprises at least some of the information received from the social-networking system; and at least one of the data transmitted to the wireless device (104, 1230) is limited or prioritized, based at least in part on social-networking information associated with the user, wherein the wireless device (104, 1230) is configured to generate operating power for the wireless device (104, 1230) from the RF signal; receive the data transmitted by the RF transceiver using the RF signal; and communicate other data to the base station (102, 400) using backscatter communication; wherein the data is transmitted without the wireless device activating any first visual alerts that would require more operating power than can be generated from the RF signal, wherein the wireless device substitutes the first visual alerts by a second low-power visual alert for which the level of operating power that can be generated from the RF signal is sufficient to notify the user that data has been received. a wireless device (104; 1230) associated with a user of a social networking system; and a base station (102, 400) comprising: a network connection configured to receive information from the social networking system; and a radio frequency transceiver configured to generate, using a processor of the base station, an RF signal and communicate with the wireless device using backscatter communication and to transmit data to the wireless device (104, 1230) using an RF signal, wherein: the data transmitted to the wireless device (104, 1230) comprises at least some of the information received from the social-networking system; and at least one of the data transmitted to the wireless device (104, 1230) is limited or prioritized, based at least in part on social-networking information associated with the user, wherein the wireless device (104, 1230) is configured to generate operating power for the wireless device (104, 1230) from the RF signal; receive the data transmitted by the RF transceiver using the RF signal; and communicate other data to the base station (102, 400) using backscatter communication; wherein the data is transmitted without the wireless device activating any first visual alerts that would require more operating power than can be generated from the RF signal, wherein the wireless device substitutes the first visual alerts by a second low-power visual alert for which the level of operating power that can be generated from the RF signal is sufficient to notify the user that data has been received. a network connection configured to receive information from the social networking system; and a radio frequency transceiver configured to generate, using a processor of the base station, an RF signal and communicate with the wireless device using backscatter communication and to transmit data to the wireless device (104, 1230) using an RF signal, wherein: the data transmitted to the wireless device (104, 1230) comprises at least some of the information received from the social-networking system; and at least one of the data transmitted to the wireless device (104, 1230) is limited or prioritized, based at least in part on social-networking information associated with the user, wherein the wireless device (104, 1230) is configured to generate operating power for the wireless device (104, 1230) from the RF signal; receive the data transmitted by the RF transceiver using the RF signal; and communicate other data to the base station (102, 400) using backscatter communication; wherein the data is transmitted without the wireless device activating any first visual alerts that would require more operating power than can be generated from the RF signal, wherein the wireless device substitutes the first visual alerts by a second low-power visual alert for which the level of operating power that can be generated from the RF signal is sufficient to notify the user that data has been received. the data transmitted to the wireless device (104, 1230) comprises at least some of the information received from the social-networking system; and at least one of the data transmitted to the wireless device (104, 1230) is limited or prioritized, based at least in part on social-networking information associated with the user,