Integrated marketing is a topic much in the news these days. My recent Businessweek column on the topic was one of the site’s most emailed and commented-on pieces. Yet there are many, many levels to integrated marketing, and we have only scratched the surface.

The first level might be best described as integrated marketing communications. This is where every aspect of a brand’s communication efforts–from advertising to publicity to online to social media–are integrated beneath the umbrella of a single brand idea. As simple as this sounds, most companies are still chasing the pot of gold at the end of this rainbow. It’s not easy to do.

A second level of integrated marketing might be called integrated branding. This takes the first level and extends it through the other elements of a brand’s Four Ps–not limiting it to promotion, but extending it to pricing, place and product expressions. Think Apple Store, or Target, or perhaps Nike and Starbucks. Few are the brands that have achieved this level of consistency.

Yet there is still another frontier, as touched on in a recent piece by Sue Shellenbarger of the Wall Street Journal about the use of “sounds that sell”. Audio is one aspect of what I call Sensory Branding, and it entails integrating a brand across all five forms of contact consumers may have with a product or company– sight, sound, feel, taste and smell.

This would include, of course, marketing communications, but at a much more thoughtful level–going beyond simply concept, design and copy into texture, shape, scent and other sensory expressions. And it covers all Four Ps, but goes beyond them as well–to the sound of a well-tuned Harley engine or Dyson vacuum, to the feel of a BMW suspension or Ritz-Carlton sofa, and to the scent of Matouk linens or a brand new Sharpie.

We have but scratched the surface when it comes to sensory branding. To those of us who are still working hard on integrated branding or even integrated marketing communications, call it job security. As long as we’re making progress.