This is really worrying, that there's a whole generation growing up whose personal data are being gathered and exploited, without their consent. I'm already upset that my friends have tagged me in numerous photos on FB, giving them more info than I care to. I can only imagine how much worse it would have been if that had been done throughout my childhood and teenage years..
Also to Facebook's facial recognition software, without your kids ever agreeing to it and they won't have a way to undo it once they grow up, even if they want to.