I just spent about half an hour reading up on the basics of AJAX, and have fixed some theoretical gaps in my knowledge as to how the higher levels of webpage dynamism work; I'm right up to the level of where I'd be ready to start writing ECMAScript snippets and actually building those pages. I'm not versed in ECMAScript, but given the variety of languages I know I could still effectively program in it if I had to. I'm going to have to look further into HTML5 before I actually consider doing so.
I could of course just tinker with code samples and smaller projects to play with the technology enough to understand it; my database-query-explorer toy would be a prime candidate for conversion to HTML5+ECMAScript, and I could probably use the new canvas element as a much prettier alternative to calling GNUPlot behind the scenes to make images.
I realise that I may be committing myself to being a technological dinosaur on this front (which is safe for me because as a systems wizard, it's far from my intended area of expertise), and that I'm probably missing out on being able to do some really cool things with my existing software base. There is admittedly an appeal in pushing the presentation layers of POUND out into a client-side ECMAScript app and having the policy layers hook into an HTTP-RPC-layer instead. Sigh.