Used to describe the rate at which a YouTuber or similiar public internet figure gains subscribers (or general fans). A fast clip is 1 new subscriber every 2 minutes.
*Jonathan Paula passes Dan Brown on YouTube's Most Subscribed list*
Dan Brown (from his video 'DAN GOES CRAZY, GETS NAKED!'): I still remember, when we first became friends you had a measly 20,000 subscribers, I mean, hah- you were nothing. Haha, we did a collab, and then what do you know!? You were on the map. You began gaining subscribers at a fast clip.