Simon & Schuster and the marketing company ipsh! recently lost a court decision after spamming mobile phone owners with text messages promoting Stephen King's new book. The Telephone Consumer Protection Act currently limits the use of autodialing technologies
So long as consumers incur any sort of direct "per transaction" cost for the traffic they receive on mobile devices, any marketer that tries to use those platforms for unsolicited advertisements is begging for trouble (and risking cutting themselves off from their audience permanently). It wouldn't take much for an enterprizing programmer to have a hit iPhone or Blackberry app that blocks unsolicited texts.
Rather than wasting their time and money lobbying or trying to create systems that skirt the law to advance ineffectual mass-marketing campaigns - marketers should be concentrating on developing relationships with their key audiences so that they WANT to stay connected because of the valuable and relevant communications from the advertisers.
It will be interesting to see how mobile device pricing evolves. One could imagine marketers offering to pay mobile service providers to make the cost of, say, an SMS text message free. One could also then imagine mobile service providers creating a new "service" that allows users to block advertising for a monthly fee.
Whatever happens, the current price structure can't continue as more and more people begin to use phones for mobile computing as opposed to purely for phone calls because it's ass-backwards: even though it's all just data moving through towers and pipes - users are charged more for SMS text messages and data transfer than they are for phone calls (which use more data).