Though I don't have tons of experience with YTMND, I feel that it's going to become a relic of the internet, if it hasn't already. It's style of content (one not very closely tied to "sharing") doesn't fit as well with the highly contagious type of media experiences of today. It seems more like art than "media": static, crafted works that stand alone. There are no share features, no comments, no interaction. To bad really. It's internet history, like Geocities and AOL :)
Do you remember the first time you ever saw the Hitler Dance? Personally, I think that as long as social media excists, there will be a need for YTMND. Maybe not a big one, but there needs to be a one up from gifsoup I guess.
Yeah, I think that it'll always have a place. But I think it's been succeeded by other things.