UPDATE: This feature is now out of beta and launches properly today with the 1.2.5 release! Weeee!
The 1.2.5 beta is BURSTING AT THE SEAMS with great new Minecraft features (though it really shouldn't be bursting at all – that's probably a bug). One of these new features is incorporating Mixer. Mixer is a livestreaming platform for sharing and broadcasting live video directly from in your games! It's a great way to interact with other players - take a look at the video above for a better idea of how it works with Minecraft.
In the Beta, you'll now be able to launch a Mixer broadcast from within Minecraft. Better yet, you can make certain parts of your game interactive via buttons on Mixer! So, for example, if you were doing a parkour run, you could use the /mixer command to let your viewers vote on what obstacles spawn in your path! Please don't spawn a brick wall for me to run face-first into. Yes, I know it'll be funny. Please don't do it anyway.
UPDATE: The Mixer team have put together a map specifically for this purpose! You can get it here! Some streamers have already been testing these interactivity tools out during the beta, so check out TangoTek, Impulse5V, YourMCAdmin and Direwolf to see what’s possible or join in the fun!
Mixer is part of the 1.2.5 beta on Android, Windows 10 and Xbox One (later this week). When the update launches fully, later this year, we'll be bringing these Mixer features to more Minecraft platforms. A separate mod for Java players will be coming later this year as well.