Same for me; I'm not into multiplayer at all, the people who I have added is pretty much just to see what they're playing, haha. But yeah, I also like adding people I know.
My PSN ID = Xernova
For more info, you can check the spoiler box in my signature. But it basically just says "I'm not into multiplayer" and "if you add me, include a message saying where I know you from just in case I don't recognise you by your username". That's about it.
I have a Steam account, but only use it maybe once or twice a year. So there's not much point in adding my Steam account here (heck, I still need to reinstall Steam first, lol).
PS: I have message notifications off during gameplay, so if you drop me a message on PSN it might take a while before I notice. If my profile message says ">>PS1 game<<" it means I'm playing that PS1 game, at which point I can't check messages at all. Just saying so nobody will think I'm ignoring messages, I answer them as soon as I notice them. ^^