A matrix code reader may detect a matrix code (such as a QR code), which may be displayed along with content and include information identifying the content. The matrix code reader may obtain user information associated with a social networking service and, based at least on the content information and the user information, may transmit an instruction to the social networking service to perform a social networking service function. The matrix code reader may obtain the user information and/or the instruction to perform the social networking service function from information included in the matrix code, from a non-transitory storage medium of the matrix code reader, from a user, and so on. In some implementations, the matrix code reader may determine that additional information or a confirmation to transmit the instructions is needed and may prompt a user for the additional information or confirmation.