SOAPBOX
dais, podium, pulpit, rostrum, ambo, stump, soapbox
(noun) a platform raised above the surrounding level to give prominence to the person on it
soapbox
(noun) a crate for packing soap
Source: WordNet® 3.1
Etymology
Noun
soapbox (plural soapboxes)
(literally) A crate for packing soap.
(figuratively) Any physical or media platform which gives prominence to the person on it and the views they espouse.
(figuratively) A talk about one's pet topic (or the topic itself), especially when only tangentially relevant to an ongoing discussion.
A soapbox car.
Verb
soapbox (third-person singular simple present soapboxes, present participle soapboxing, simple past and past participle soapboxed)
To give a speech from (or as if from) a soapbox.
Source: Wiktionary