The smart phone or mobile device is clearly the future of electronic communication, fixed phones and fixed PCs are increasingly used less for accessing email and online information and receiving communications.
Text messaging (SMS marketing) as a communication tool has value in certain instances. As a pure marketing communication text messages are not a trusted source unless as a communication enhacing a client order or experience from an established client/supplier relationship.
Using SMS or MMS messaging does suit certain profiles but should be used only as communication following a purchase really.
Secure communications benefit from text messaging where separate messages can be sent to customers regarding online access, or to supply an alternative route to receive password access so adding an additional level of security.