What it means
A human reads your opening hours off the page. A machine reads a block of code, usually in a format called JSON-LD, that says in so many words: this is a LocalBusiness, these are the opening hours, this is the telephone number. The vocabulary is schema.org, and it is shared by search engines and AI assistants alike.
Why it matters to a small business
It is the difference between a machine guessing your details and being told them. That is what lets Google show your hours and star rating directly in the results, and it is increasingly what lets an assistant answer somebody who asked whether you are open now. Modern site builders can add it for you, and plenty of sites have none at all.
The bit people get wrong
Marking up something the visitor cannot see on the page is against the rules and can get the markup ignored or the site penalised. If your code claims a 4.8 star rating, the reviews have to be on the page. Structured data describes what is there, it does not add anything.
Source: schema.org LocalBusiness. This page is a plain-English summary written by the Marketeer team, not legal advice. Where money or the law is involved, read the source.