New activity isn't it. This forum changed when the year changed to a new prettier looking format without the whats new button
After you click on New Activity, there are options for Today's Posts or New Posts. Or you can click up in the top right corner, where it says "You Have ___ Unread Posts". The text "Unread Posts" is actually a link.
You can also try popular threads if you like http://www.politicalforum.com/misc.php?do=page&template=Popular