I have long since stopped looking at the comments I get on my Youtube videos, because I get about thirty a day. It'd be nice if I could read them all and answer the interesting comments, but I don't have the free time to do that.
I try to keep up with messages that I get sent from various Youtube users, but I still end up getting something like ten messages a week. Recently, it's more like ten a day, which is a lot of work to answer, and if it continues, I'm going to have to stop looking at messages, too.
When it's people who are having problems with a particular part of a game or something like that, I'm always willing to help out because that's what I do as a guide writer. But when the messages are something like "check out the music video I made of [song I don't know] with footage from [anime I don't know]", I tend to skip over them.
I also like it when people make their own video walkthroughs and let me know about them. I must have gotten about thirty messages like that so far. True, I only enjoyed two them (the rest, I stopped watching partway through the first video), but I still get excited over the prospect of having a cool new video walkthrough to watch.