I'm not seeing the problem. Mozilla introduced tabbed browsing a few eons ago, and that already does what you want. As far as I can tell, most modern browsers now support tabbed browsing.
I have the forum topics page open in one tab. To read a post, I use middle-click (click with scroll wheel) to open the unread posts in a second tab. To reply, I use middle-click on the reply button. It I want to get back to the start of the thread, I can go to the first tab (the topics page), and middle click on the thread to open to the first page (and opening post).
Jesus was a liberal hippie
™ Version 4.2
