I believe youtube's takedown process isn't strictly a DMCA feature. From the submission it looks like it's not even a takedown, it's just a thing where google is letting someone put ads on other people's videos if they claim copyright and possibly bully them, but it doesn't look like they're serving DMCA notices.

Edit: The comment at https://news.ycombinator.com/item?id=4122258 was posted while I was typing this post and is a lot more informative. :)