Gossip take up to 2/3 of converastion time. It's suggested role is to defend aggainst free riders[1] (parazite), or basicly against ingustice.
In social wars, partisans may try to harm other by smear campain, carried by gossip.
Gossip, I think is dervied from the need to talk with others and look at problems from other perspective. In people with low self-esteem and FFFF or system 1 decison making system, the gossip is used to get reasurance that we are OK, and the others are bad.