If you have no idea what the hell I'm talking about, don't worry, this video probably isn't for you. If you want to find out, here's a link: http://derpy.me/Count

To open that second window, just click the number of posts in the thread list: http://i.imgur.com/aGWi1ZQ.png

ReloadEvery for Firefox: https://addons.mozilla.org/en-us/firefox/addon/reloadevery/‎
ChromeReload: http://derpy.me/wUDoG

If you only have one monitor, you can use AlwaysOnTop to make sure the whoposted window is always visible: http://derpy.me/R510e