1) Electronic communication 2) Electronic messaging 
In a mobile context, messaging generally means the two-way systems for text messaging, such as CMT and GSM SMS, and their later developments EMS and MMS. GSM cell broadcast messaging however, is a one-way technology, like paging.
[n] - the sending and processing of e-mail by computer
electronic messaging noun the sending and processing of e-mail by computer
Sending text messages by phone; see text messaging