I was looking a bit at this nervemail client mentioned on Mozillazine. It's a WebMail-like application that generates everything via scripts that get loaded on an as-needed basis. OK. The loading stuff only when needed is good. Also, the fact that data gets passed back and forth rather than having giant blocks of HTML loaded every time one wants to do something is good.
I'll point out the things I didn't like then.
The obvious thing is that it is trying to emulate a mail client UI rather than a WebMail UI. That is fine. But it isn't a good idea to use a language for creating documents to do so. The scripts create the UI by using createElement to throw a bunch of HTML elements on a page. Most of the HTML is not semantically meaningful. It uses <u> elements and <table> elements in ways that don't make sense. Or at least I think they don't. It's hard to tell, since everything is in a difficult to understand script. Why not just use HTML files directly? They're more readable.
Or better, why not use XUL, which has the distinct advantage of already having semantically meaningful tags to handle menus and trees and the like. And you don't have to spend weeks or months re-implementing menus like 20,000 other sites do. If it was implemented in XUL, this application would be quite interesting. It would be like a remote version of Mozilla Mail.
There was mention that the nervemail application uses only W3C and DOM standard things. Yet, the code contains numerous references to innerHTML.
Anyway, I do think that there are some interesting ideas behind nervemail, yet it is still based on some concepts we should be moving away from. More on that soon.