Community "leaders" can choose a custom avatar, banner, and set specific rules for the page. They also have the power to ban and timeout channels deemed inappropriate for the group. Like Reddit, then, the onus is on Twitch's community to monitor these hubs and stop them from spiralling out of control. The advantages are numerous though: now, a streamer can reach a specific, relevant audience on a broadcast-by-broadcast basis. If I'm usually playing League of Legends, for instance, but fancy streaming DJ Hero one night, I can target a music or rhythm games group that will know and appreciate what I'm doing. For streamers, that's a useful way to diversify and reach new people who might become loyal subscribers.