Short Message/Messaging Service, commonly abbreviated as SMS, is a text messaging service component of most telephone, Internet and mobile device systems. It uses standardized communication protocols that let mobile devices exchange short text messages. An intermediary service can facilitate a text-to-voice conversion to be sent to landlines. Mobile marketing, a type of direct marketing, uses SMS. The global SMS messaging business was estimated to be worth over US$240 billion in 2013, accounting for almost half of all revenue generated by mobile messaging.