MMS stands for Multimedia Messaging Service. It’s commonly referred to when people describe sending multimedia content such as pictures (e.g. wallpaper), sounds (e.g. ringtone), or short video clips through a phone’s messaging network. This is different than sending content via email or an online service.
MMS was invented to extend the core capability of SMS (Short Message Service), which allows only for the exchange of alphanumeric characters up to 160 characters in length.
Often times when people say MMS, they are in fact referring to binary content. Binary content is delivered to a mobile phone as a file available for download from the mobile web rather than instantly appearing within a messaging application.