One of the most important new features for the PS4 will be the DualShock 4's Share button, which will allow gamers to distribute their in-game accomplishments to the world almost immediately. Mr. Yoshida, who's no stranger to social media, clearly thinks that this is one of the most important next gen updates to the system, and that it holds a lot of potential for both Sony and consumers.
Unlike anything, other than the internet itself, social media is becoming more and more pervasive in the gaming world. Sony's announcements around social media was one of the cornerstones of their presentation, and is likely something that is going to continue to grow and expand for them, as well as the industry as a whole . For the next generation of gamers, and the next generation of consoles, sharing your experiences with your friends is clearly going to become more commonplace, and easier to do it. Sony's partnerships with Facebook and Ustream are clearly signs that PlayStation are looking to get their games in front of as many people as possible, to showcase just how great they are.
Just take a look at the example they provided last night on the "Killzone" Facebook page for "Shadow Fall."