In communications, flood control is a feature of many communication protocols designed to prevent overwhelming of a destination receiver. Such controls can be implemented either in software or in hardware, and will often request that the message be resent after the receiver has finished processing.

Internet forums often use a flood control mechanism to prevent too many messages from being posted at once, either to prevent spamming or denial-of-service attack

Denial-of-service attack

A denial-of-service attack or distributed denial-of-service attack is an attempt to make a computer resource unavailable to its intended users...

s. Internet Relay Chat

Internet Relay Chat

Internet Relay Chat is a protocol for real-time Internet text messaging or synchronous conferencing. It is mainly designed for group communication in discussion forums, called channels, but also allows one-to-one communication via private message as well as chat and data transfer, including file...

 servers will often quit users performing IRC floods with an "Excess Flood" message.