I once did a place called like the sub4sub station. You had to sub to other people and other people would sub you back for points to have people sub them. And they just unsubscribe anyway. I soon realized I just felt worse. I Unsubbed all the people and asked them to not sub me. I am now getting very successful without that website, and it turns out my secret weapon has been interacting with the comments. Please, everybody, don't do sub4sub, bots, or even the subscriber train. They are all pointless, and will only bring you down.