^ For me it's more the culture I don't want to be a part of, not that I think the whole world will know my bank account once I sign up.
On that note though, i've seen with Mrs. Ace that FB changes their terms/format slightly every once and a while and all of a sudden stuff she though was only accessable to one group is all of a sudden opened up for all to see. Usually this can be fixed by going back and adjusting to the new settings, but it sure seems like you lose control over the info you decide to share, even if it was only meant for certian people...
Oh yeah, and I'm not on twitter either