Forgive my ignorance on these types of things. If I was to go to a YouTube video, and open the nostrichat extension, leave a message, is it only visible to people who also open the ext on that same video? Or does it get posted to all clients as well?

Is that what the nip does? Separates different forms, so things like a nostr blogging platform would only show long form blog style notes, and doesn't show up on damus or amethyst feeds, for example?

Either way, this is really awesome. I love the innovation