According to researcher Daylam Tayari, they have discovered an internal API used by Twitch that makes reference to what the company is calling the Brand Safety Score. From what we can tell, it seems to suggest that streamers could be given a score based on various factors like their age, if they have been suspended, Twitch partnership status, and more.
Presumably this will be used to help advertisers find streamers that they want to work with. According to a Twitch spokesperson, “We are exploring ways to improve the experience on Twitch for viewers and creators, including efforts to better match the appropriate ads to the right communities. User privacy is critical on Twitch, and, as we refine this process, we will not pursue plans that compromise that priority. Nothing has launched yet, no personal information was shared, and we will keep our community informed of any updates along the way.”
As Engadget notes, this rating system is similar to one that other platforms have used, like YouTube, Twitter, and even ridesharing apps where drivers might choose not to pickup passengers with low-ratings, and passengers might want to avoid drivers with low-ratings as well.