"We've come around to saying that Nike is a marketing-oriented company, and the product is our most important marketing tool." — Phil Knight: Co-founder and former CEO of Nike (from Nightengale.com)
Of course, you’ve seen Nike on TV, so you know that they do advertise, but building the marketing into a product you want your users to “wear” every single day sounds a lot like radio to me.
Is your product built to be your most important marketing tool? (Marketing: “placing your product in the mind of the customer, so they can use it.”)
Before you start to advertise, think like Nike.
Is what comes out of the speakers so special and unique in every single minute that it creates buzz and loyalty among the folks who are now aware of it?
If so, you’re ready to advertise and grow your cume. If not, it’s time to research, innovate and develop the "sole" of your on air product to the point that it exceeds expectations.