While music and podcasting gingerly shake hands, podcasting and advertising are doing high-fives. Podcasters know they are sitting on a gold mine since their overheads are low, and they can create fresh content faster than corporate radio can. Advertisers will find these niches very useful, and worth a shot. Take a look at the companies registered at the Portable Media Expo in September this year.

Podtrac is an interesting company to watch, because it takes on the role that advertising agencies (at least their media buying departments) once controlled. They serve podcasters and advertisers, providing the former with targeting and tracking tools. Free measurement is also thrown in for Podcasters. Revenue will be through ads, sponsorshipe and sales.

You could tell how new the business model is by the fact that the site has a link to a page titled What is podcasting. Presumably many of the older ad agencies are still wondering if this locomotive too, like Blogging, will roll through their bucolic land and disrupt their picnic.