Here's the condensed rundown on why this isn't a good idea:
1. Someone writes something and posts it. You respond. You give your heart to that post and that person. Others respond. And then three hours later the OP takes it down. How do you feel?
2. You write something in a foul mood and go to bed. Next morning you are or aren't still in the foul mood, but you're too embarrassed to read the responses, so you take it down. Later on, you gain your nerve to read the response, (quite surprised that the responses are still up even after you took down your post.) Some people gave you encouragement. Now what they said makes no sense, because no one can tell what was said that required that encouragement. Maybe someone went off on you, but others came to your defense. They all look like loons, because there's nothing to compare it with.
3. I'm mad at good-ole-so-and-so and really blast her in the middle of the night. I say things so bad a pimp would be horrified, but I don't want to be kicked off the board, so I let my mob read it, giggle, and congratulate me in PM. Meanwhile some newbies join the site, read it, and think good-ole-so-and-so must really be a creep. That's their first impression of her. And then I remove it so I don't get caught.
4. You write a post about something few people talk about thinking you're the only one in the world who goes through this or thinks this. Then you take it down later fearing everyone would think you're a freak. Six months later, someone is googling because she has this problem that no one in the world would understand. The result page shows that someone (you) had the guts to speak up about it. Relief floods through her once she realizes she's not the only one in the world like this... except one thing. She still feels like a freak and still keeps hiding, because you took down that post. THAT close to realizing she's not alone, only to walk away feeling as alone as ever. Maybe more so, because she truly must be a freak -- a one-of-a-kind freak.
I found this site because I read something in scripture that seemed to be totally different from anything I've ever heard or read about that verse before. I wanted to know if I was off my rocker nuts thinking maybe there was something in what I thought. I may well be off my rocker thinking that, but at least I found a young man from NZ who asked if anyone else thought the same thing on here. Most people who responded didn't get what he meant. I did. And I learned it was okay to say it out loud. Good thing he didn't change his mind later. His post was two years old and he's still here. So am I.
Don't think, simply because you change your mind, your words don't have effect on others. If you say something dumb or because you're in a bad mood, you can always acknowledge that later -- or not. But when you share and then take it away -- you're not just effecting yourself. This is social networking. It means something, even the regret.