"People see Facebook as a way to privately share their life with friends." Fits what people in my family think (I'm not a user). I haven't thought it was a good

"People see Facebook as a way to privately share their life with friends." Fits what people in my family think (I'm not a user). I haven't thought it was a good choice for that, because huge sites tend to attract hacks. If private sharing is the reason most people go there, then I'd think FB would want the UI for privacy to be very transparent (at the "here's what happens when you click this, and here's what non-friends will see" level). Twitter's UI surprised me. I used the 'public' setting; as their docs described it, I expected @someone messages would be seen only by people following me -and- the recipient. Wrong. When I googled my t-name, all my tweets, including those @ messages, were wide open to the whole net. Whoa!