Here's this: in my opinion, Facebook, is supposed to be really, really flaky. What I mean is, not really the spot for heavy-duty friendship stuff. Well, not the "profile page" anyway. And it's not the end of the world either way, but the thing is, unless you're 15, there should be not one even remotely negative comment on a profile page. It's a meaningless page anyway, except for the fun of shooting back and forth quick and friendly updates on your life and the lives of friends you might not have seen for years (scads of re-connected YWAM friends-- I LOVE that element of facebook!) or ones you'll see at work tomorrow. It's no big deal. It can be hilariously funny and is often highly entertaining. But when it comes to my profile page, if there is ever anything that I personally translate as too much information about my life (per ex., info that a close friend has but doesn't realize that I'm not really sharing yet or ever-- hasn't happened in a long time), or if it makes me a little uncomfortable, or feels passive aggressive in any way at all, I delete it. No big deal at all, but it doesn't stay.
But the fact that this is even something I think about as a 37 year old woman reminds me about how stressful this kind of stuff is to my students. What I do so casually, and hope that my other adult friends pay little attention to (a comment disappearing or not responded to), a teenager might not be able to do so easily. They're so keenly aware of the behavior of others toward them, taking so much so personally... stressful. Typically, once I delete something I forget about it. There was one friend that I did drop (in the distant past-- long time ago), but otherwise I just don't think about it any more: facebook is not a real place. It's an elaborate message board. An easier way to keep up with my beloved former housemates and friends in high school, YWAM, and college than the phone calls we don't really have time to make (plus, several of them don't even live in the country any more). But it shouldn't be a place where important things happen. My advice to some of my kids who were having a myspace fight (of course, they didn't take this advice): never try to solidify plans on a profile page, discuss intimate relationship issues, discuss OTHERS' relationship issues, apologize, forgive, ask out, or break up on a profile page. It's careless and inappropriate and if you get hurt...well, you kind of walked into it.
You won't (hopefully) find me doing or saying anything deep or meaningful on a profile page, and if I receive something that feels too personal on a profile page, expect to see it disappear. It's no big deal. As adults, if we get our feelings hurt on Facebook, we should delete our profile because it has become worse than a waste of time.
These are simply my opinions, but it seems like we spend so much time telling kids how to be online and we don't pay that much attention to the fact that adults are getting as tied up with this world of virtual stupidity as the children are, and that is, to me, a dangerous combination of passive aggressive behavior mixed with opportunity to make a public spectacle of yourself or your friend-- as adults, the consequences can be more far-reaching than with teenagers, but more than that, it's embarrassing.