Heads up, Creators: On Dec 13-14 you may see a noticeable decrease in your sub count as we remove spam subscriptions. If spam is removed, you'll see a YouTube Studio alert: https://goo.gl/qGDBvX This should help give you confidence that the subs you do have are real fans!
This will remove however growth, as more subscribers for channels means they will be featured on the home page more often based if off viewers similar interests, in turn creating less opportunities for the creator.