Well, something like that. According to an article in today’s New York Times, it serves a serious purpose among social groups -- helps keep people within social norms (read the part about how people who want to leave work early are shunned by their colleagues in a group whose ethic is to work horrid hours).
The study didn't quite say that it was ok to gossip, but since it is so prevalent *and* serves to keep people in line, maybe it's ok after all?
Reminds me of Laura Sizer's question: what purpose do emotions serve (anger, love, etc.)? Why did we evolve to have these emotions? Today's question: Why did we evolve to gossip?