I have a friend whose 10 year old daughter has a myspace account (I have one too). Her daughter asked me to add her as a friend, and I couldn't do it (my profile is set as private and only "friends" can view it) because I couldn't guarantee that she would not see or read adult content that would not be appropriate for her.
I'm probably as guilty as anyone when it comes to putting too much info out there. I am very comfortable with it, and I think younger generations are even more so because it seems so normal to them (they've grown up with it!).
I do think it's important to think about who may read or view what you post. Even if you delete or edit it, someone may have stored it away so it is there forever.
Don't post things you don't want the world to know.
My parents actually read my blog (my brother too) so I don't post things I wouldn't want them to read. There are times when I have posted things and thought maybe I shouldn't have because the person I wrote about might stumble across it.
But being a SAHM I don't have an employer to impress. I guess I might in the future. Maybe I should think about that.