Okay, I did sub4sub for a little bit (most of my first 80 subs were from sub4sub), and it is a horrible idea. The people who do sub4sub are mostly just wanting to get a higher subscriber number for themselves and don't care about the channels they are subscribed to. Some of the people may be kind and watch, like, or comment on a couple videos, but the vast majority will not even look at your channel and unsubscribe after a day or two. Also, sub4sub means you are not growing your channel because people genuinely enjoy your content, but rather, they subscribe because they are getting a subscription of their own. This means that there are channels with hundreds, even thousands, of subscribers with horrible video quality and low view to subscriber rates. All you get from sub4sub is a bunch of empty subscribers. Another thing is, if you do sub4sub and are not actively watching the channels you are subscribed to, you add to the point that all you get are empty subscribers. Fortunately for me, I stopped doing sub4sub early, and my channel has blossomed because instead of focusing on the amount of subscribers or views I got, I focus on making each video better than the last. When people see good content, they will want to see more, subscribe, and actually watch more of your videos when they come out. However, if your subscribers are just coming because they want a subscription out of you, they're not going to watch your videos regularly. When your focus is on the numbers and not about the content you make, it becomes a problem, and sub4sub is all about the numbers. So, my point is to stop doing sub4sub if you do it and focus on improving your content instead.