Soapbox

A soapbox is a raised platform on which one stands to make an impromptu speech, often about a political subject. The term originates from the days when speakers would elevate themselves by standing on a wooden crate originally used for shipment of soap, or other dry goods, from a manufacturer to a retail store.
The term is also used metaphorically to describe a person engaging in often flamboyant, impromptu, or unofficial public speaking, as in the phrase, "Get off your... meer