Update: The PlayStation Network is slowly coming back to life following an outage that lasted around two hours or so. Just about everything went offline, with users unable to sign in, access online features, or play online games.
Hopefully that's the end of that.
Original Story: The PlayStation Network is having difficulties, it seems. Reports started coming in earlier tonight, and it appears to have only gotten worse over the past hour or so (at the time of writing). According to Sony's official PSN service status page, every aspect of the network is experiencing issues.
In other words, you might not be able to sign in to you account on PS5 and PS4, access your friends list, the PlayStation Store, or other online features. This includes playing games or game modes that require an online connection.
Hopefully it all gets fixed sooner rather than later. It's been a long, long time since the PSN was taken offline almost completely.
We'll update this article as and when the situation changes.