Sony launches PlayStation Communities app for Android and iOS

According to developers, PlayStation Communities is supposed to make it easier “to stay in touch with your fellow PS4 gamers while away from the console.” This means that it will only work with PlayStation 4 consoles, not with previous generations.
You can even talk to them within the application. PlayStation Communities comes in handy when you can't find enough players for a raid, as the app may help you fill out your party.
Furthermore, you will also be able to see community profiles, view a list of communities that you are already part of, as well as see who else is in your community. Obviously, you can discover additional communities that might suit your interests.

source: Sony