Helen Keegan has one of the most comprehensive descriptions of mobile marketing that I've ever seen:
"Whenever I meet someone new and I tell them what I do for a living, they usually assume one or both of the following:
1. That mobile marketing is sending junk text messages to get people to subscribe, unwittingly, to a mobile content subscription service. Ergo, mobile marketing is bad.
2. Mobile marketing = marketing using SMS (text messaging)
Neither assumption is true so this is my lowdown on what mobile marketing includes."