Subscribers gained

Studio reports gross additions rather than net change. A period can therefore show healthy subscribers gained while the total barely moves, because people unsubscribed at the same time. YouTube attributes each subscription to wherever the viewer clicked, which means a video published two years ago keeps earning credit today. Anything it cannot place, such as a subscribe from the channel page or from search, lands in an other bucket. The number worth watching is subscribers gained per 1,000 views on a single video, because that tells you which idea converts rather than which one got lucky with reach.