If you mean posting a thread just to post your youtube channel then the answer is no. That's something we classify as advertising and is not allowed.
The only way we allow youtube channel links is as a text link in your signature. You are allowed to post videos in specific stickies we have on WoW general and class forums as well, but they need to be in those stickies, NOT as seperate threads.
The issue is that if we allow one person to link their youtube, then everyone will want to post their youtube and it would drown out any normal discussion in the waves of advertising threads.