Not really lounge-ish but doesn't seem to fit any of the other categories as this is not OS specific. Oh, and it really isn't a question, just sort of curious who else is interested in this aspect of the web's future.
I've just started to play with WebVTT which can be used to provide track and subtitle and chapter information to HTML5 video via the track element.
My current experimentation involves both subtitles and captions.
subtitles are for things that are spoken in the movie, captions are for sounds in the movie that someone who is hearing impaired or has the volume off would want to know happened.
In Chrome, I can see that there are subtitles / captions but they aren't showing for me, even though I had read Chrome has support.
In FireFox, I had to enable it as an experimental option and then it worked - with both subtitles and captions - but FireFox does not respect things the line:x% directive when the text needs to be placed at a different location.
In Opera, support of the actual subtitles itself is much much better, except it seems I can't do both subtitles and captions (two different track nodes), it seems I have to one or other.
Now I'm using Opera 12 on Linux as there is no Opera 20 for Linux AFAIK. However I tried in Opera for Windows and result was same, though I have to check the version installed there.
Anyway, I hope WebVTT support continues to improve, I know there are JS players out there that emulate what native WebVTT is suppose to do, but there are several reasons why I personally don't want a JS player taking over my HTML5 media, so I'm hoping good native browser support comes soon.
Looks like Opera does have the best support right now as far as displaying the content, just needs a little work on using more than one WebVTT source at the same time.
A good write-up on it: http://dev.opera.com/articles/view/an-introduction-to-webvtt-and-track/
Personally I see this as more than just an accessibility feature, I suspect search engines will start (if they haven't already) to parse WebVTT track files when indexing multimedia sites.