said 1 year, 3 months ago:
Mobile marketing is huge and most effective where impulse actions are required. For example, redeem code now for discount on purchase or to go to site for something that expires soon, and many other similar types of instances.
Yes, there are privacy/opt-in rules and legal language that should be included with the messages to extend communication. Most mobile marketing companies know what they are and abide by them.
One more thing, mobile works best when part of a greater campaign. Good luck.