I realise this is mundane, but sorry Robert Scoble, I feel duty bound to disagree with you as to whether video content delivered via RSS should be called a 'podcast':

"Some groups call what they do "screencasts" (cause they are doing Flash videos of what they are doing on screen). Other groups call them blogcasts, but that term hasn't been accepted outside of a few small groups yet."

Podcasting has become synonymous with 'audio'.  Look what Wikipedia's podcast entry - my bold:

"It is distinct from other types of online audio delivery because of its subscription model, which uses the RSS 2.0 XML format with an audio/mpeg enclosure. Podcasting enables independent producers to create self-published, syndicated "radio shows", and gives broadcast radio programs a new distribution method. Listeners may subscribe to feeds using "podcatching" software (a type of "aggregator"), which periodically checks for and downloads new content automatically."

To be fair the entry does go on to say the same delivery technique can deliver video, but this is single mention in a sea of an audio focused definition.

Now I like your "podcasting in my mind is "Personal On Demand Casting", comment - nice, but...The iPod is associated with audio...it may well do photos and video in the future too, but can it break its brand from the audio shackles? Sony Walkman marketers tried and failed  Maybe Apple can do this, but be sure - today is known as an AUDIO device.

In the same way you believed what Channel 9 does is best described as video blogging, or vlogging (urgh!), (you were right by way, now you're wrong ;-), the act of recording your screen is what screencasting is (not just in Flash btw, any video output format), or as Wikipedia puts it (I know 'cause I created the original entry, ably iterated by others since):

"A screencast is a recording of computer screen output, usually containing audio narration typically published as a video file."

As for the terms being used by a few small groups, that maybe so, but 'Screencast' beats 'Blogcast' in a Google Fight any day of the week :-)  I think screencasting will always be a less active area in terms of the number of productions compared to video blogs or vlogs (see Google Fight again on this) - it takes someone fairly geeky to record their computer screen in action and publish this as a video file. In contrast publishing handycam-created content on the web will be much, much bigger in terms of adoption. But screencasts and vlogs are 2 different things. Don't confuse them as the same.

In my final effort to persuade you...Say I 'm going to give a present for your birthday and I ask you what you might like as a present. You'd like a book, you say - you love reading...Now, as you know, there are lots of different kinds of books.  Novels & non-fiction.  Audio books & brail books.  But I decide to give DVD video, and when you ask why, I reply "'cause in my mind, books and video are type of media that can be delivered by post, and since you wanted a book, I thought I'd give you a video.

Books and DVD movies are not the same.  Audio and video (with audio) are not the same.  Podcasts and Screencasts are not the same. Why name two different things as the same thing?

Update...trackbacks are flakey so adding manually :-(

Robert notices (trackback)
Frank Arrigo asks a good question in my comment:

"so, what's the collective term? or is your argument such that there shouldn't be one?"

I respond lamely: "Good question Frank. I don't know, maybe 'casts'? Blogcast, Screencast, Podcast?"  Want to add to this: I don't have anything against there being a collective term for content being delivered via RSS.  My suggestion is lame, but I don't think it should be 'Podcasts' for the reasons given above.  I also want to point out that audio files, video files - whatever - don't need to be within an RSS encolusure to be called a podcast and screencast: in fact most content is right-clicked downloaded on embedded within HTML.  These methods won't go away because of the advent of RSS.  Another thought....if you go to iPodder, the Podcast Network, PodcastAlley.com,  or any other podcast-related directory, feedstore, etc, you'll find they ALL deal with audio. Not a single video-clip will be found... Anyway, I'm rambling...

Update 14 July 2005:

Inside Microsoft (trackback):

"Of course, plenty of Microsoft employees use Apple’s player, and use the word podcast. The more important debate is why the hell are we naming the medium after a single product? I realize the iPod is popular today, but what about in three years? Everyone is aware that the “pod” in podcasting refers to the iPod, not anything else. Personally, I like the term “RSS Radio” (which allows for “RSS TV” instead of the terrible “vlog” term). What do you guys think?"