What is DMCA takedown?
Short answer
A copyright notice under the US Digital Millennium Copyright Act requiring a host or search engine to remove infringing material.
It applies to copyright only: your photographs, your text, your video reproduced without permission. It does not apply to someone writing something unflattering but original about you.
Filing a knowingly false DMCA notice carries legal liability. Services that file them against ordinary criticism expose their clients as well as themselves.
Why it matters
It is the fastest removal route that exists — and the most abused, which is why platforms scrutinise it.