I tested this already with two blogs. 1.Go to youtube. 2.Search videos with much views releated to your blog/site like music,games... 3.Make comment example : Nice video!Take a look this great blog : eguideart(dot)blogspot(dot)com 4."eguideart" this must be written because its your site/blog name. 5.Next day or faster you should be indexed. I commented 5-10 videos.