Currently, public sub counts are abbreviated in most but not all places across YouTube. In August, we’ll make this more consistent by always showing abbreviated sub counts publicly. Creators: You’ll still see your full sub count in Studio! Learn more → http://yt.be/help/abbrev-count …pic.twitter.com/pmaKk4EU4k
Many creators sometimes do "subscriber count livestreams, where they comment on live the exact growing number of their YouTube channel, on sites like @SocialBlade. And for viewers it can be interesting to use those sites to see how rapidly their favorite channel is growing. (2/?)