So Google Stadia is the name of the game and as @killthenetpredicted, it is a full streaming service. All the computing power is done in Google's datacenters on a custom AMD GPU with 10,7 teraflops and is then streamed to your Chrome device of choice. The promise now is 4K output on 60FPS, with support coming "later" for 8K and 120FPS. There will be heavy integration with Youtube. For example, seeing a trailer of a game on it ends with a play now button, which takes you in-game within 5 seconds. Further there will always be a 4K stream of your game available to broadcast or save on Youtube. You can use Google Assistant to help you on with a game, without the need to close it and open up Youtube for a tutorial. The only real hardware announcement (besides the computing unit in the server they use) is a new controller. It features a built-in microphone for Google Assistant, a button for instant streaming. It connects through wifi, so it is not connected with your device but with your gaming session. This makes seemless transition from one device to another possible without the need to reconnect the controller. Google is teaming up with developers (Assasin's Creed Odyssey, DOOM Eternal and the creators of Rime are involved). Dev kits have been send out to hundreds of developers. The platform supports Unreal Engine and Unity. Google will also develop first party titles through their new studio Stadia Games and Entertainment. They will support cross-play and cross-progression if a developer wants it. The service will launch "2019", and the game line-up plus pricing will be announced on a later date. Perhaps E3?