Update: Spaces has been discontinued as of April, 17th 2017.
Spaces, the newest app which lets users create a space with just one tap for any topic. Sharing is key as anyone can be invite via messaging, email, social network or whatever, (that's what google said). The biggest features that stand would having built in Google search, YouTube all without having to leave the app.
Google has stated that this app will rolling out as of 05.16.2016. for Android, iOS, desktop & mobile web for all Gmail accounts.
Source: View the original blog post.
Post was last updated: 05.05.2018.