https://techcrunch.com/2020/02/20/twitch-to-top-40-million-u-s-viewers-next-year-forecast-says/

Twitch, the Amazon-owned streaming service for gamers, is poised to surpass 40 million monthly active viewers in the U.S. as of next year, according to a new forecast from eMarketer out on Thursday. By 2023, it will reach 47 million viewers. Currently, the analyst firm estimates Twitch has 37.5 million viewers in the U.S. who tune in to watch at least once per month.

Officially, Twitch reports it has over 3 million active monthly creators and over 15 million average daily streamers, per its own website. But it focuses on metrics like minutes watched and concurrent viewers to paint a picture of its size and growth.