Structured Data
Also known as: schema markup, JSON-LD
A description of what a page is about, written into the page in a form search engines and AI can read directly.
A human reads a page and understands that it is a dentist in Tampa with these opening hours. Structured data says the same thing in a fixed format, so software does not have to guess.
It is the difference between leaving a note in your own handwriting and filling in the form. Both carry the information. Only one is readable at scale.
It does not create rankings. Anyone selling it that way is selling something. What it does is reduce the chance of being understood incorrectly, which is a smaller and more honest claim.
Where it earns its keep is consistency. Generated from the content rather than hand written per page, it is right on every page instead of right on the three somebody remembered.