Get your marketing message delivered directly into people's ears, and do it in a (rather) cheap way. Just launch a podcast service, or if you dare just a little bit more, create your own online and mobile (!) radio station.

Two recent examples of "audio marketing" (I know it a bad naming! any better idea?):
- Amazon has just debuted on the Web with Amazonwire, a podcast featuring exclusive interviews with authors, musicians, movie directors and other people behind the products they sell (via Random Culture).
- Bacardi has just presented BACARDI B LIVE Radio which will stream exclusive music content 24/7 through the Internet and directed to mobile phones across the world. On Mobhappy you find a good analysis of this idea.