A citation is the moment an answer engine points at a source. Having composed its reply, it names where the information came from — a business, a site, a particular set of words — either as a small linked source beside the answer or as a mention woven into the sentence itself. It is the closest thing the new landscape has to being recommended by name.
In the old world a site chased a high ranking, because a link near the top of the list earned the click. When the answer is given directly and the click may never come, the citation takes the click's place as the thing worth winning. To be named as the source is to be vouched for — the engine is effectively telling the person asking, this is where I would look, and so should you.
Citations are earned, not bought. Engines tend to name sources that are clear, specific, and backed up elsewhere — a business whose facts are stated plainly, whose claims are borne out by reviews and mentions across the wider web, and whose site is easy for a machine to read. Original, concrete information earns a name-check far more reliably than vague, general copy that could belong to anyone.
A citation is word-of-mouth, rebuilt for machines. Once, a trusted neighbour said 'go to them' and that was enough; now an assistant does the recommending, at enormous scale, and a citation is it saying a name aloud. Nobody can demand one; it can only be deserved — by being the clearest, most trustworthy answer to the question people are actually asking.
