Dangerous comments! What, where and how to post on YouTube?

Is it possible to write these or other things in the comments? And in general, how anonymous are the comments and can you be tracked by them? In some cases, such as VK or Odnoklassniki, this question can be answered easily: you can't write anything seditious, because they track everyone. But in the case of Western services, like YouTube, the situation is much more complicated.