From The New York Times:
Juicy gossip moves so quickly – He did what? She has pictures? – that few people have time to cover their ears, even if they wanted to. Gossip has long been dismissed by researchers as little more than background noise, blather with no useful function. But some investigators now say that gossip should be central to any study of group interaction. People find it irresistible for good reason: Gossip not only helps clarify and enforce the rules that keep people working well together, studies suggest, but it circulates crucial information about the behavior of others that cannot be published in an office manual. As often as it sullies reputations, psychologists say, gossip offers a foothold for newcomers in a group and a safety net for group members who feel in danger of falling out.
When two or more people huddle to share inside information about another person who is absent, they are often spreading important news, and enacting a mutually protective ritual that may have evolved from early grooming behaviors, some biologists argue.
More here.