Commodities is a system extension introduced in AmigaOS 2.0 that enables programs to monitor and manipulate input events system-wide before they reach applications. It operates through the Commodities Exchange, where programs (called commodities) register as brokers to provide services like global hotkeys, mouse acceleration, or screen blanking. The system functions as an input handler in the input.device chain, allowing utilities to intercept keyboard, mouse, and other input events without requiring modifications to individual applications.