I set it so that every time someone replies to one of my comments on YouTube, I get an email notification. This is useful to me because I actually like the discussions that can sometimes be had in YouTube comments (not always, but enough to keep the notifications).
I'm annoyed though because Gmail is my primary email service, and I like to keep it clean. But I've ended up getting tons of YT notifications. I know there's a way to create a kind of "Smart Folder" that will automatically put everything from YT into it, but I don't know how to activate it. I think it has something to do with "Labels", but I would need someone to walk me through it, there don't appear to be any walkthroughs or explanatory guides out there.