Presumably people have gossiped for about as long as they have been able to speak. However, the 'truth content' of the average communication seems very low.

Take something as simple a speed limit sign. That sign is not literally 'true', it simply refers to what the calculation for penalties will be based if you exceed the unstated actual speed limit. Reporting is at best a game of telephone, social media ends up so many hops from what actually happens to be nearly completely separated from reality.