Broad category of ideas - a game the fans can play together.
A more specific variation - a game that the streamer somehow configures to be specific to him/her in some way, such that playing the game (and we can put “game” in quotes to make clear it could be almost any kind of experience) is relevant to all the fans.
For example, assume for a minute that music rights were not an issue. You can imagine a game of “name that tune” using the streamer’s favorite music. That way it is personal and interesting to each channel, but still fun and engaging. Now, if you think this idea is lame, GOOD. I’m not a game designer. It’s meant to illustrate the kind of experience we speculate could work.