Without this feature some places that I'd like to send a reader may involve multiple jumps within the new address itself. To get back to my forum then requires them to take their browser back through the same set of steps. This is frustrating and confusing to many of my readers who are not very computer literate.
In the meantime, I'll just place those links within a post so that the forum window doesn't go away when the reader does.
I had actually forgotten there was a mod for it: http://custom.simplemachines.org/mods/index.php?mod=3816