You can check your friends list, send text and voice messages, and even slap on cute little stickers like Drake from Uncharted, Ellie from The Last of Us, and Knack from... Knack.
Now you may be thinking: hold on Mark. Hang on. Woah now. Hold up. Stop right there. Halt this article. Wasn't this already available in the PlayStation App?
The answer is yes. It was. But it isn't anymore. In the latest update to that app, Sony has removed messaging. So you'll need to have two apps to do that. Brilliant!