Well I say forget messaging. There's too much energy spent on messaging, a concept traditionally measured by impressions. Ad agencies use impressions to measure the success of a campaign, and to justify their cost to clients. But how does an impression affect sales figures?
They don't. It's even difficult to figure how an impression really influences brand recognition. So why do so many ad agencies use impressions to measure campaign success? Tradition.
The progressive way to measure advertising success then should be measured in action. How many people sign up for your e-mail newsletter? (You have one, right?) How many people link to your YouTube videos? How many people are in your company's Face Book friend profile? How many people visited your booth at that grassroots marketing event?
Answer these questions, then you can spend time on developing your messaging.