The E4X support I'd mentioned in my web trends predictions post has just shipped as part of Firefox 1.5 Beta 1. Though the the release notes track a little bit of oddness in what's required to take advantage of the support, it's still a very good sign.
Of course, I might be wrong about some of the other points I've raised; a smarter man than me offers his assessment.
Good news: E4X is likely to be on by default in Firefox 1.5 Beta 2. See https://bugzilla.mozilla.org/show_bug.cgi?id=309242.
Good news: E4X is likely to be on by default in Firefox 1.5 Beta 2. See https://bugzilla.mozilla.org/show_bug.cgi?id=309242.