Audio, the sometimes forgotten stepsister of video, is still a worthwhile pursuit for some media companies. But the key to getting anyone to download and listen to your podcast lies in creating the right content, format and length for your audience.
Creating good content should be a no-brainer, but the format and length pieces will take some experimentation. I'm a huge a podcast junkie, and in my exploration and research of podcasts for companies I've worked for, I've found a variety of formats that work well for different audiences. On the other hand, I'm not surprised when audio shows with poor formatting are canceled.
Here are a few podcast formats media companies have successfully deployed, sometimes using a combination. (I'm excluding shows like 60 Minutes that are just the complete audio versions of a program intended for radio or television, although this can and does work well in some cases.) 
Chatter
One popular format for podcasts consists of experts discussing topics in a roundtable format. Just because it's conversational, however, doesn't mean it should be freestyle. Shows that do well in this format are produced and edited, making sure topics are planned in advance and don't get stale. Slate'sCulture Gabfest and Political Gabfest podcasts are well-produced, weekly conversational podcasts, presenting a few hot topics in an entertaining and informative way.
Live shows
If you have a devoted audience, recording live is a way to make audio more social and interactive. For example, the popular TWiG (This Week in Google) podcast is streamed live and available to download later as a video or podcast. Audience members tuning in live can interact with each other and the hosts through a chat room.
Interviews
One of the oldest forms of audio journalism continues to be relevant in podcast form. For print publishers, interviews are an effective mechanism to present extra materials.The New Yorker Out Loud features a weekly interview with one of the writers behind a big story in the magazine. The conversational, behind-the-scenes approach is a good illustration of how an interview podcast can complement the written word.
Narrative/eclectic
It's often too much work to produce an entire show via podcast (rather than picking one format), but it can work nicely for media companies with the resources. For example, The New York Times' Bits: Tech Talk podcast packs a few formats into one tightly edited show. The show balances a few regular features (such as a weekly explanation of a tech term) with interviews and chatter.
Round-up
A "round-up" is how I refer to podcasts anchored around highlighting the biggest news of the week. The New York Times' Front Page podcast briefly summarizes the day's top stories, similar to how I skim the headlines in my inbox. I'm not convinced this rehash format works very often, but it makes sense for a publisher like the NYT to include it in its repertoire. Many consumers want a high-level view of what's going on in the biggest newspaper in America, and this podcast does the job. For other publishers, the round-up format might work better when sprinkled with other content, like interviews or commentary.
How-to
Podcasts are often an opportunity to provide listeners a useful tidbit of information or advice, either as supplement or a standalone product. Grammar Girl, beloved by grammar nerds like me, is a short and useful podcast that dives into one grammar topic every week. This format could be especially suitable for niche or B2B publishers trying to convey useful information appropriate for audio.
What other formats should publishers consider for audio content? Please share your ideas or examples in the comments below.
