Twitch's social network-like Friends feature just got more useful if you want more company for streaming or broadcasting. A new feature called "Activity Sharing" will notify your entire Friends list if you're doing something interesting so they can join in. Conversely, you can check your Friends list to see what others are doing and join in, as shown in the GIF below. Users can keep broadcasts or streams private, if they prefer, by un-ticking the "share my activity" box.