Abstract: In order to invite individuals to join a social network, telephone contact information of a user of the social network is extracted, with the user's permission, from a phonebook associated with a telephone application on the user's portable electronic device. Then, the extracted telephone contact information is shared across different platforms to the user's desktop computer, and telephone numbers in the extracted telephone contact information are identified. These telephone numbers are associated with other portable electronic devices, and with individuals that are not currently members of the social network. After receiving confirmation of a telephone number from the user (e.g., via the desktop computer), the location of the associated portable electronic device is determined. Based on the telephone number and the location, an invitation to join the social network is conditionally provided to the portable electronic device, via a Short Message Service (SMS) message.