As someone who has a background in creating very large and detailed pictures from tiny and seemingly insignificant pieces of information, I come down on the FB thing with HPL2008.
Frankly, as potentially damaging as I think FB could be to a person, no one honestly knows where it is going and what it will become with respect to how data on you might be used either intentionally or unintentionally.
articles like this one discuss how easily, in the modern world, sites like FB can become more dangerous than people think for reasons that seem harmless to someone not overly concerned with their own personal security.
Social Security Numbers Deduced From Public Data | Wired Science | Wired.com
the bottom line is that if your FB profile shows your state of birth (this can be guessed by ratios involving your friends' states of residence and other info even if it does not), date of birth (FB will alert friends to this as the day comes round for many of you, and name, your identity is at risk.
at NSA we considered any pair of facts about anyone which could be linked to be very valuable and could usually go very far from there in acquiring a third, fourth, fifth until huge files were created. in other words, your name and address seen together or your name and age or your name and birth date or your name and the high school you graduated from are all enough to create a much larger and more invasive picture.
i shred anything which has two facts about me in one place. and i can tell you, i burn through shredders.