But this thing is customizable, albeit not very easily. An example on how I use Facebook: I created a list of friends that are able to see my wall. It is a sort of a whitelist. If you ask me for friendship and I grant it to you, you just see some albums and the generic info page. I have to put you explicitly in the whitelist to let you see my wall.
Even if you are in the whitelist, I still can select what you see: I have a list of people from work, close friends, people who speak a particular language and so on. Everytime I post something to my wall I can decide to which lists it's visible and to which it's not. It takes a little to set up but after that it's easy to manage.
That's the thing....it wasn't even on my wall. It was a comment on someone else's page who wasn't a mutual friend. The link to the comment was deleted and they still found it, probably through fbs "look what x said on y's page " feature.
Even if you are in the whitelist, I still can select what you see: I have a list of people from work, close friends, people who speak a particular language and so on. Everytime I post something to my wall I can decide to which lists it's visible and to which it's not. It takes a little to set up but after that it's easy to manage.