In this article, onAXIS compares PlayStation Network and Xbox Live:
"Okay, first, lets start off with interface, below we have the interface for the PlayStation Network, and the interface for Xbox Live.
Now, if you take a look, Xbox Live lists "Messages, Friends, and Chat" usually with an ad under Xbox Live when logged online showcasing a new download or game on the Marketplace. While the PlayStation 3 lists the friend addition, blocking, and message box, all under one XMB icon."