I broke down and bought an IPod a few months ago. One of my favorite uses for it is listening to podcasts (audio and video programs that anyone with the correct equipment can make and which the audiences download to their computers). Now that I'm more experienced as a user, I can offer some advice for present and future podcasters. I should say that some podcasts I really like don't follow all of these and that this is intended as constructive criticism.

1) Keep Your Podcasts Relatively Short:
Most professional podcasts are from 1-20 minutes in length. That should tell you something. People usually listen or watch while on the go, and often don't have time to listen to something really long. Just because many radio and TV programs are an hour long or longer, that doesn't mean that podcasts should be that long. Podcasts are a very different medium than television and radio.

If you have an hour long podcast that stands up after editing (see point 6), break it up into 2-3 podcasts and run your episodes more often. You can produce them all at once and upload them at different times. You will make your podcasts more attractive to listeners.

2) Try Not to Be Too Captive to the News Cycle:
One thing I noticed is that I don't update my podcasts every day. I doubt other people do too. I also often will get a dozen or more past episodes podcasts.

My listening habits aren't that linear either. My moods change, and the same podcast I will listen to three times one week I will not get to for three weeks after that. When I find podcasts that are new to me, I often will download episodes from weeks or months ago.

The upshot is that what is topical when you create your podcast will be old news for many of your listeners. Keep allusions to the latest items in the news cycle short and try to illustrate more lasting points with those allusions.

3) Be Sure to Show Your Personality:
One thing you can offer with your blog that nobody else can is your personality. One of the things about podcasts that make them so interesting is that you get to hear voices and personalities that vary from the bland, narrow range of corporate media.

4) Focus on One Broad Area for Each Podcast:
If you have a passion for PHP programming and a passion for cooking, don't put both on the same podcast, much less the same episode. If you are trying to teach people how to speak Farsi, a long English diatribe about the best kind of donuts probably won't be too helpful for your audience.

Think about your audience. How many people are going to be interested in both subjects? How many of those people will want to listen to or watch a podcast about both at the same time?

5) Try to Have More Than One Host and to Find Guests:
More voices make podcasts more interesting. Also, interaction can improve the quality of ideas presented. You probably don't want to listen the same person you don't know that well for an hour (or even 20 minutes) unless that person is absolutely fascinating beyond belief. The second or third voice can really break things up.

6) If You Have Time and Expertise, Edit Your Podcasts:
If you don't have time to do this or to learn how to do this, skip to the next point. However, if you have one hour of raw material, you probably have about 15-30 minutes of content that is really worth listening to or watching. Also, you may think your bloopers are hysterical, but podcast bloopers are so common that they all are boring now. If you have lost your topics list or other piece of information, definitely try not to subject your listeners to hearing about it for 2-3 minutes.

7) Be Careful About Getting Self Referential:
For much of your audience, your latest episode is their first episode. If you are on episode 154, don't expect many people to know about or even remember what you said in episode 21. A lost audience member is a bored audience member who soon will be an former audience member.

Please put other advice for podcasters in the comments. Improving the quality of liberal podcasts helps get our points across more effectively.