According to the PS3: “Sets whether to notify when Friends are online or when a message has been received from a Friend.”
Only options are: Display/Do not Display.
Is there a way to make it so you only receive notifications if a friend messages you? It’s a pain to constantly see “XYZ is now online/offline” every 5 seconds when you have a big friends list. I don’t see why we need to get notified when a friend turns his PS3 on or off, only when they message you would be fine.