[sandworm101]

ContentID is the DMCA. It isn't a DMCA takedown, but it is a scheme designed to satisfy Google's DMCA obligations. Viacom was perhaps the fire behind its deployment, but it is the DMCA that dictates that the system exist.

s512(c)(1)(C) "upon notification ... responds expeditiously to remove, or disable access to"

"Expeditiously" is the key. That is, today, understood to mean now, not after the weekend or once Bill comes back from lunch. On a giant system like Youtube, it requires an automated system.

[ascagnel_]

It brings YouTube into compliance with the DMCA, but it goes above and beyond. It automates only takedowns -- putting content back up is a process that must be manually done by a user. There's seemingly no human presence you can reach out to as an uploader. There's no way for a user to upload content and explicitly flag it as "I own this, if anyone claims copyright on it they're wrong" (see NASA having their own landing footage taken down by an overly-zealous Content ID match). There's no way for someone to upload a work as royalty-free or public domain (I've heard horror stories about that more than a handful of times).

Add to this YouTube's poor view of fair use (they've come under fire in the past for misrepresenting fair use in a copyright education video), and it's a recipe for disaster.

[xsmasher]

"upon notification of claimed infringement as described in subsection (c)(3),"

[sandworm101]

Ok, then s512(c)(1)(A)(iii)

"[Safe harbour applies] if the service provider— upon obtaining such knowledge or awareness, acts expeditiously to remove, or disable access to, the material."

"Awareness" would apply even absent a formal DMCA takedown pointing to the content. So after the first, Youtube is 'on notice' for repeats even where those don't get new takedown notices ... ContentID.