Schema markup is a shared vocabulary that tells search engines and AI tools what each element on a page is, not how to display it, but what it means, so the engine can extract clean facts, trigger rich results, and cite the page accurately.
Across UC's 146-article Australian corpus audit, 15% of audited sites shipped no JSON-LD schema at all, and among the rest only 24% included FAQPage and 9% LocalBusiness, the two types AI engines lift from most cleanly.
HTML tells a browser how to render. Schema tells the machine what it's looking at. A block of text that reads "Melbourne, VIC 3000" looks the same in HTML whether it's a postal address, a review location, or a line of body copy. Add an addressLocality property from the schema.org vocabulary and the ambiguity disappears. Schema.org was launched in 2011 by Google, Microsoft (Bing), Yahoo and Yandex as a shared standard: "a collection of shared vocabularies webmasters can use to mark up their pages in ways that can be understood by the major search engines." The formats are Microdata, RDFa, and JSON-LD. JSON-LD is the one Google recommends and the one you'll see in any modern implementation, a script block in the page head, separate from the HTML, clean to read and easy to validate.
Google's structured data documentation describes two uses: rich results (star ratings, FAQ dropdowns, sitelinks, breadcrumbs shown directly in search) and entity understanding (the machine building a confident model of what your business is, where it operates, and what it offers). Both matter, but entity understanding is the one that compounds. A Brisbane plumber's LocalBusiness block with a consistent name, address and phone, an Organization block with logo and sameAs links to LinkedIn and Google Business Profile, and a Service block naming the actual trades, these form a machine-readable identity card that every engine, including ChatGPT and Perplexity, can read and trust.
The visibility impact is real. According to Sixth City Marketing's schema research, pages with schema markup can see 20–40% higher click-through rates through rich results. That gap comes down to real estate, a FAQ dropdown or star rating dominates a plain blue link in the SERP.
The FAQ Schema type is one of the highest-leverage implementations for a service business: question-and-answer blocks marked up and ready for extraction by answer engines and AI Overviews. Schema implementation is a standard part of the technical layer we build in SEO & AI Visibility, because a page without it is harder for every engine to read cleanly, whether that engine is Googlebot or a language model compiling a citation list.