Lateral diffusion is the process whereby information can be spread from one node in a social network to another, often in a selective way, and can rapidly traverse an entire population, but preferentially to those nodes likely to be interested, or needing to know. Messages or information are also subject to query and modification en route. This is in contrast to central media where one message or perspective is broadcast to a large number of people simultaneously. Thus lateral diffusion can be said to occur in a lateral mediaThis is similar to how rumours, gossip and jokes rapidly spread. But note that each sender can be selective: a sender wouldn't necessarily tell a superior a joke he might not approve of. Senders also tend to pass on information to those who they know from personal experience would be interested or need to know.