Interesting bit of news related to podcasting this morning.

eMarketer announced that the 2007 podcast audience reached 18.5 million active users. It’s good to take any projection with an ounce of skepticism, but the same study estimates the 2112 podcast audience at 25 million.

When you start segmenting that audience, however, it’s hard to see how the average newspaper podcast garners enough regular listeners to drive sufficient revenue.

That’s no reason not to try, however, but more on that below.

One question not answered by eMarketer is how they define podcast. To many people, podcasts are more than audio shows, but include episodic video as well.

Could video be driving podcast growth?

I know I prefer video “podcasts” to audio, but that could be just me.

Video, however, seems to represent great revenue opportunity because of the larger overall audience for online video and the visual nature of video advertising.

Either way, newspapers should tread lightly here. It’s one thing to take the lo-fi approach with illustrative video, or even periodic story video. It’s an entirely different matter with episodic audio or video.

Any time you expect an audience to develop a habit for a regularly scheduled shows, quality is paramount — and it’s not just production quality. The content must be engaging and the talent behind it must be finely honed. The demand for top-notch on-air audio and video talent will only grow as podcasting grows.

That talent isn’t likely to come from traditional broadcast, because of the more informal nature of online media, which is a mystery to highly trained professionals from traditional media.

In other words, these growth numbers, if true and they hold, represent opportunity for newspaper companies and journalists willing to try new things.