#new anchor
Why does it use "#new" as the anchor instead of the message id if the new link already has the msg id in it? Doesn't that seem weird? You could remove some extra markup and make the links work the same for everyone, instead of having #new go to a different message for everyone. You could use some JS to check if the anchor/id doesn't exist and then look for #new. What's with new topics having "?topic=$topic.msg0"?
Some pseudo This might actually work:
function moveToNew()
{
var hash = url.substring(url.indexOf('#')+1);
if($('#' + hash).length == 0) {
location.hash = '#new';
}
}