Mobile instant messaging (MIM) is poised to take over SMS. MIM is very similar to SMS, in that you can send and receive text messages on your cell phone; however, MIM is capable of more flexibility.
MIM is simply an instant messaging program stored on your cell phone. Think of Yahoo Messenger, ICQ, AIM or MSN Messenger for mobiles.
MIM provides many benefits over SMS. SMS cannot store user information. When you send an SMS, you can only tell the telephone number you are texting. With MIM, configurable profiles are available. These can provide information such as names, email addresses, home addresses, or any other info the messaging service provides.
Matthew Kirk points out on Textually.org:
“Of every 100 messages - including texts, emails and picture messages - sent by users without mobile instant messaging from their mobile phone or computer, 38 are text messages. Once consumers start using mobile instant messaging, the number of texts falls to 23 per 100.”