It's Game Time!
Okay I wanna make things straight right now. If I am going to do blog commenting just for SEO, consider it useless. Correct me if I'm wrong, but I don't think it's effective anymore in the latest Google algorithm for good. But I am going to do blog commenting for gaining more direct social exposure and engagement, I would consider this method useful. But make sure that the comments look natural into the eyes of the blog owner and the readers. Right now, if I want to gain exposure to my website, I am not thinking anymore about ranking, but to engage with others.