You can skim a podcast in a number of ways.
First, if you go to the podcast's website, there is generally a very short summary of what that episode is all about. If you are in iTunes, you can look at the description of the episode you are interested in. As a rule, podcasters really do seems to be filling in the descriptions, so look for it.
Second, Apple added some extensions to the regular RSS file format that podcasts use. The extensions allow breaking a podcast into chapters, and including photos. This allows a podcaster to make their episodes very skimmable.
Here is Apple's brief on the subject.
Here is more detail on how to do it.
This tutorial from O'Reilly Make explains how to do it - and is very rich in photos showing. It shows exactly how to do it - and exactly what the results are.
When the podcast feature was first added to iTunes in mid-2005, Apple introduced the ChapterTool for setting up chapters and such. If you want to spend zero money on software, that is one option. There are free GUI front-end applications to run it for you now, so you don't have to be a command-line jockey or XML-lover to use it.
To be honest, ChapterTool is tedious to use. Podcasting in general requires setting up a bunch of XML. Including Chapters and Photos that an iPod and iTunes can display just adds to that.
Which is why Potion Factory introduced Podcast Maker - a very easy drag-and-drop GUI application for he Macintosh. It takes care of all the complexities of creating your XML, breaking things up into chapters, and including photos in the podcast.
The GarageBand and iWeb applications included in Apple iLife '06 are also equipped to set up podcasts with chapter marks, include photos, and so on. They are easy to use, and designed for non-technical people too.
Extending by adding tags outside those specified in the RSS 2.0 standard is controversial.
However, eXtensible Markup Language is extensible, after all. That is why the word is in its name! XML namespaces provide an elegant way for defining new elements and attributes to XML documents like RSS. Apple extensions use the itunes namespace.
Yahoo and Microsoft have defined their own extensions to the RSS standard as well. So, the XML and RSS standard offer the possibility of doing this. And both a premier web company and an Apple-competitor are doing it too. Hopefully, everyone making audio players will support podcasts and this feature from Apple you want. If they do not, that is hardly Apple's fault. They published this spec on the web ages ago and it is still there.
Third, there are ways you can playback a podcast faster. You can speed it up and play it at double time or whatever speed you want.
Fourth, you can always <u>skip around</u> in a podcast. If there is a boring section, you can skip through that. Likewise, if you miss something, you can go back and play it again.
Podcasts are an audio or A/V medium. They are not text. You cannot skip over the big words in a podcast. You can however skip forward seconds, minutes, or whatever... at a time. Both the iPod and iTunes make it easy to skip around - and easy to see how far forward (or back) you are skipping.
The chapters Apple introduced work fine in podcasts if you are playing them on an iPod or iTunes. They aid <u>skimming</u> a lot. That is one of the thing they are there for.
Considering iPod+iTunes is what most people use, and the name is pod-cast after all, that is not an unreasonable thing to use.
Apple had no problem adding support for this feature, not to mention podcasts in general, to millions of iPods that were already sold prior to June 2005.
I would assume Microsoft and other less popular MP3 players have an ability to be updated with new features like this too. If not, I can see why they are less popular. Apple ads new features to the firmware of both new and old iPods every year.
The problems you cite with podcasting, being able to skim through the material - presumably by going faster or skipping parts - are very much part of the capabilities of podcasts, MP3 files, and MP3 players. The chapter and images features also give you things borrowed from the book metaphor that help you skim.
I have personally seen a man drive 55 m.p.h. on the DC I-495 beltway - during rush hours - reading a newspaper propped up against the steering wheel! While that scared the hell out of me, if that man was listening to a podcast - I would have felt a lot safer.
While you make some valid points about things that would be nice to be able to do, you overlook that there are ways you can do them. You are also overlooking the great things that having in an audio medium makes possible.