The WSJ is running a lengthy Q&A with Courtney Jane Acuff, an associate director of Denuo, the Publicis Groupe consultancy about the hurdles facing the mobile advertising sector:

• Customer concern over privacy
• Lack of opportunities (inventory)
• Marketers still need to understand and learn how important mobile marketing is
• Consumers are not ready for video ads
• The marketplace is so crowded with players: carriers, advertisers, aggregator agencies and so on--difficult for first time mobile marketers to know who to call

For more on Cuff's take on mobile ads:
- see this article from the WSJ (sub. req.)