CheatCC says - "PS4 Share Play was the feature that was going to change the gaming world. Basically, it allows gamers to let their friends play a game they don’t have, by directly streaming it to them. The way it works is one player starts playing and streaming a game while another player watches. The first player can then give up control to the watching player whenever he likes to give them a taste of the action. Not only does this allow gamers to share their favorite games with each other over the internet, it allows for a lot of interesting streamed experiences. For example, a fighting game pro can let YOU choose his character for the next match. Cool right?"