I think a lot of people should watch this video. It’s a vlog from farfromsubtle, a preferred “let’s player” of mine, that explains how content id, and flagging on videos works from the perspective of the one receiving a flag/content id notice. It is VERY long, but very informative. And it is definitely worth a skim, at least.
The video does include, of course, references to his own video gaming show (Video Games Awesome) and how new events will affect it. Feel free to skip that, if you want, but I still hope you will watch to understand flagging, content id, and copyright removal processes.