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!
What exactly are spam subscribers? I’m concerned if a smaller channel gets a shoutout and with it a large number of subscribers very quickly it will be registered as spam and their progress negated.