positive feedback

Positive feedback is when feeback acts in the same direction as initial changes, leading to escalating change. A familar example is the feedback effects when a micropohne picks up sound from speakers. Typically positive feedback leeds to runaway behaviours and exponantial growth, but it can be useful to create deliberate rapid change so long as there are additional mechanisms to limit the extremes.

Positive feedback effects often lead to long-tail distributions and power laws, and this can be seen in social networks when those with large numbers of connections are most likely to gain new ones.