Sony teamed up with Samsung to enable users of the latter's 2015 Smart TV lineup to play PlayStation games without needing to have a console. Samsung's new TVs will come with an integrated app that will let you connect to the PlayStation Now service and buy PlayStation 3 games that will be streamed to your TV over the Internet. All you need is a DualShock controller and a solid Internet connection. The initial library will feature 200 PlayStation 3 games.
It will be interesting to see how the systems operate when hundreds of thousands, and millions, begin to use these new TV's. The early games are notably from the PS3, and not the PS4. There are likely a few reasons. PS4 games require more computation and have better graphics, so it might not be feasible at this point to process all of the data for millions of users at a remote location, let alone provide the bandwidth to stream it with acceptable performance.
This could also be a litmus test for Sony. Simply offering PS4 games online would remove the need for consoles. Sony is still in the business of producing consoles, even if they make the lion's share of profit from licensing. Testing the new service with the PS3 will allow them to observe and analyze how the new service impacts overall console sales somewhat safely without risking their flagship product.