Every text messaging initiative geared to drive sales typically would begin with a Bulk messaging activity. You may need to address a group of people within a geographic region or community and send a bulk message to all or a few of them from the list.
The messages can be text (SMS) or Multimedia (MMS) based and follow the same mechanisms to set up and send as a single SMS.
Bulk Messaging can be done manually as well as in an automated way. See the use-case for Automated Campaign Setup for automated bulk messaging.
Bulk messages from a List
You can send bulk messages from the List View of Salesforce for Contacts or Leads.
Similarly, you can send bulk messages from Campaign Manager, Salesforce Campaign, and Reports.
For more information about sending bulk messages, see Send Bulk SMS.