I just checked something on facebook and actually found it was more public than I thought - there's a subtly hidden link on the privacy options, above the basic default ones where you just go through the friends only check off list. Go to basic profile information - I did that and managed to make myself pretty much totally unsearchable now. If you aren't logged in, you can't see my profile at all. It gives you an error page. My email is unsearchable even if you are logged in. That's the level of privacy I prefer.