DabKick VR is a new app for Vive I'm helping launch, so I'm massively biased when I say this, but I think it's a unique twist to "social VR", in which the virtual world space is accessible not only to people wearing headsets, but also people accessing the same app from their smartphones:
[W]e think social VR can’t succeed unless the vast majority of non-HMD owners can also participate in the experience. This is why we’ve created an immersive, virtual theater, where Vive users can enjoy both video and images together with DabKick app users connected via their iOS and Android phones — all represented as avatars in the same virtual space, together... Maximum concurrency per session: Technically up to 100,000, but feasibly, up to 200 avatars in the entire theaters watching together.
Lead developer Balaji Krishnan wrote a post explaining why this cross-platform approach may work where pure VR experiences may not: