Would it be possible for you to put a 'new posts' link on all the pages?...that way you wouldn't have to keep pressing the back button on the browser to get back to the new posts when u r reading the messages.. Unless you can already do this some other way :?
If you click on the main logo in the top left of the page, this will take you back to the main page where you can see the (x) new posts again - though I suppose this doesn't help really !!!
There is another option. When you click on the (x) new posts text and the new page opens, if you right click on the new post then select 'Open in New Window' it will do just that... open that link in a new window leaving the page with all the new posts still open in another browser...
There are two other things that would be helpful to add, if possible. One would be to repeat the "view previous/next topic" link at the bottom of each page. This would save having to run back to the top of the page each time. The other would be a "skip to new posts" link on each topic page, which can also save a lot of time, especially if there have ben a lot of postings. Whether or not either of these is possible, keep up the good work!