Google has given us a way to have YouTube parties - from an app.
Google's startup incubator, Area 120, allows employees to work on approved projects during their "20 per cent time". The latest project from that incubator is Uptime, a mobile app that lets you meet up with people, share YouTube videos with them, engage using stickers, and more. It is described as a "place to share and watch videos together with friends... watch, chat, and have fun".
You can search for videos using the app, and it'll help you find friends with common connections. You can also engage with friends while watching videos through comments, stickers, "sparkles", hearts - and all your activity is accessible from the profile page. In other words, Uptime is making the experience of watching YouTube videos a more group-centric thing - even for people who aren't in the same room.
It is only available on iOS, and not Google's Android, at least at launch. Also, Uptime does not allow you to watch and share paid and premium content, such as movies and YouTube Red. You can learn more about how the app works from its FAQ page.
We could see Google testing the waters with this app before integrating the core features into the actual YouTube experience. Otherwise, we'd personally think it would be cool if the app considered adding the ability to record or stream your own videos.