DMCA and content stealing related question
 

Is there some accurate metrics to determine if content is stolen or not, like for example if 10% of page content has content of other page or something like that?

What matters is if your content is on the page, without your authorization.

I just had another 20 sites removed from Google, that were either offering free downloads of my stuff, or using my metadate (title, author, description, artwork) to hijack traffic to some unrelated site of theirs.