Whooping, yass-ing, yelling out and singing along seemed part of the package at the preview I saw. (I loved the show but hated the experience).
It's funny - sometimes it can totally depend on the context. I'm not usually a "raucous" audience member myself, but when I saw the show in Boston I was going through a very stressful emotional time in general - and the show, along with the crazed audience response, really picked me up and helped me feel much better for a few hours. I think I really needed that. :-)