Read the CMS blog entry here.
Look over the Perplexity Poll (PDF) here.
Andy Havens at CMS looks at this from a church perspective with good insight. I'd like to make a couple of comments from a media perspective:
(1) Keep your message simple. I prefer a one point sermon to the traditional three-point variety.
(2) Offers should be simple and straightforward. Make the offer so clear the viewer (or listener in radio) has a binary decision - yes or no.
(3) Whatever your proposition and whatever the medium, keep it clear, simple, and binary.