Social networking and defining friends

I saw this post on the Facebook blog, and thought it was interesting. It seems too many people on all the different sites just want to try and get as many people as possible on their friends lists, not realizing the implications of doing so. In the entry she directly says "Friendship on Facebook is, in and of itself, a privacy setting." It's unfortunate that people don't realize this, and then when the view of it changes they get freaked about the information they're giving to all these people they don't trust. If you don't trust someone with all the info posted on there, why list them as a friend? If only they'd post this entry somewhere inside the system as a reminder to people (but then how many would read it?).