If you play with Facebook Connect, your Facebook friends will be displayed in the Friends tab.
When you are in the lobby, you can find the Friends tab in the lower-left corner. If you tap the Recent Players button on the bottom of your screen, you will see the list of players you have been playing with recently. You can add them as friends by tapping the Add green button.
Also, now you can find both your Scatter Direct and Inbox in the same tab in the bottom-right corner of the screen.