FISA (Fighting Internet and Wireless Spam Act) is an opt-in law, but not arduously so. Marketers shouldn't be afraid. After all, you were already required to respect opt-in permission, if you wanted the best possible ability to get your emails delivered, right?
Don't be afraid of the private right of action, either. As Ken Magill previously reported, the barrier to entry for a lawsuit is fairly high, due to the "loser pays" provisions extant under Canadian law.