Finally got a URL set up for the little chatting application. And actually sat down and played with it for a while with the 3 browsers I have handy (Firefox 3.5, Chromium and IE 8). Good news is that (after having to fix a known jquery-on-ie bug), it all seems to pretty much work. Bad news is that there's lots of little fit-and-finish bugs, UI elements that just don't quite work. Most are little things that can each be easily coded around, but there's likely a solid day's work in there with all of them.
One that's very annoying is that Chromium seems to get "tired" after a while if there are too many incoming messages. I gather something in JQuery gets borked, as the symptom is basically that "K" is not defined (ah, the joys of compressed js). Speaking of which, I ran the JS and CSS through YUI compressor. I've done that before, but tonight I realized, why not just gzip compress the minimized results? Saves rather a lot of transfer; almost 500KB down to 71KB for the js and from 34KB down to 5KB for the CSS. Seems to work perfectly fine in the 3 big browsers. Of course, once I finished and actually tested, it doesn't really make much of a difference to the user, as everything is in the cache after the first page-hit.
I'm really not satisfied with the main query-speed so far. Seeing ~400ms for the page load. Will have to track that down if I'm going to have even a dozen simultaneous users, let alone hundreds. The streaming seems perfectly fine, it's just the initial page-load that's taking far longer than I'd like.
I also spent quite a while trying to set up Ajax login... then finally decided that I'll have to just go with non-Ajax login for now; the repoze.who.friendlyform stuff just isn't set up to do async login and fixing that isn't something I want to spend time on right now.