Earlier today we got a look at a patent filing from Google for a controller notification system that will inform users when their online pals are getting up to things. It's all very vague, and in fact Google emphasized that the accompanying illustration is not representative of the actual device, but only intended to provide "a fundamental understanding of the disclosed subject matter and the various ways in which is may be practiced."
We speculated that the filing might be related to whatever it is that Google is expected to announce during its GDC keynote next week—a keynote that the company is now teasing with a brief new video that is even less informative than the patent filing. There's a stadium tunnel, a backstage hallway, a cavern, a garage, a cargo plane ramp, some kind of fantasy fungus funnel, a spaceship launch bay, and a crumbling castle corridor—the common theme being that each of them are staging areas or portals through which you will step on your way to more interesting places and things.
(In case it's not sufficiently clear, the video ends with a rapid recap of each, with the viewer thrown face-first into the bright, mysterious light that awaits on the other side. Onward to destiny! Or something.)
Google said last year that it's interested in launching a streaming game service, and joined with Ubisoft to conduct a streaming gameplay "technical test" using Assassin's Creed Odyssey. Given all that, I don't think anyone will be overly surprised if that's what this is all about, particularly given the "Gather Around" tag that ends the video, suggesting (as I read it, anyway) that some sort of group/social play thing is in the offing.
On the other hand, maybe Google Plus is mounting a comeback. We'll find out on March 19, beginning at 10 am PT/1 pm ET—if you can't be at GDC, you can catch the livestream on YouTube.