Funnily enough Dattebayo's on my facebook friends list. I have just a handful of serebii friends on facebook. With the serebii exception I only accept friends who I know in real life, and have had a few conversations with. I barely ever add people first, unless it's a really obvious addition like a best friend irl who's only just joined the site. I do have quite a few friends, mainly because I've moved a couple of times now and I've got a broad base of acquaintances.I occasionally get a request from a newbie member I've never even seen before. Those are the kind of requests I turn down - ones from people who've never said a single word to me. All you have to do to get on my friend list, really, is have a conversation with me. It needn't even be through VM or PM; in-thread chatting works too.
Speaking of Dattebayo, I miss him. He was a pleasure to talk to.
I have a warm relationship with all my contacts online, with the notable exception of a couple of family members who add me on sites and then pointedly ignore me/don't get along with me. But I'll be seeing them at weddings and funerals so I don't want to cause friction over facebook, and besides, family is family.